Cattail.Nu Watercolor Course

Core Supplies

If you already own equivalent supplies, don't buy these unless you personally decide you want or need them. These are the things that will give absolute beginners the most versatile starter set.

Paints

Winsor Newton Tube paints (<15 ml, until you know if you like the color):
Blue Red Shade - Winsor & Newton Professional Water Color Tube, 14ml, Blue Red Shade
Permanent Alizarin Crimson - Winsor & Newton Professional Water Color Tube, 14ml, Permanent Alizarin Crimson
New Gamboge - Winsor & Newton Professional Water Color Tube, 5ml, New Gamboge
Cobalt Blue - Winsor & Newton Professional Water Color Tube, 5ml, Cobalt Blue
Burnt Sienna - Winsor & Newton Professional Water Color Tube, 14ml, Burnt Sienna
Permanent Rose - Winsor & Newton Professional Water Color Tube, 5ml, Permanent Rose
Lemon Yellow (aka Hanza) - Winsor & Newton Artist Professional Watercolour Paint - 5ML Tube (Lemon Yellow)
Permanent White Gouache (not watercolor chinese white) - Winsor & Newton Designers Gouache Tube, 14ml, Permanent White

Brushes

Make sure you get watercolor brushes so the bristles are soft and will hold a lot of water.
Loew-Cornell Round Watercolor #12 (rounded tip, but takes a beating for mixing water/dry paints) - Loew Cornell, 7020-12, Ultra Round- Golden Taklon
Silver Black Velvet Round Watercolor #8 (comes to a sharp point, but should be gently used) - Silver Brush 3000S-8 Black Velvet Short Handle Blend Squirrel and Risslon Brush, Round, Size 8
If your budget wont allow the below, you can use the Loew-Cornell #12 above for your washes.
Watercolor Mop (large round brush for wetting/backgrounds/sky) - 
Silver Brush 3009S-034 Black Velvet Short Handle Blend Squirrel and Risslon Brush, Oval Wash, 3/4-Inch OR Princeton Artist Brush Neptune, Brushes for Watercolor Series 4750, Quill Synthetic Squirrel, Size 6 There's more variety of brush stroke on the Silver Black Velvet oval wash (does really pretty petal shapes, and an easy narrow/wide by twisting). The Neptune holds about two to three times as much water/paint and is excellent for quickly covering really large areas. If you intend on doing large paintings, the Neptune is worthwhile.
Watercolor Flat 1" (backgrounds/sky/effects) - Sapphire Brush by Robert Simmons- One Stroke Wash Brush 1 Inch

Brush size comparison:

Paper

Arches 300g (150lb) Cold Press Watercolor (or Hot Press, if you prefer), block, pads, or sheets, whatever you prefer. There's advantages and disadvantages to all of them.
Arches Watercolor Block, Cold Press, 9" x 12"
Watercolor Pad, Hot Press 9"X12"
Watercolor Block, Hot Press 10"X14"
https://www.youtube.com/watch?v=D_AnLl0PMlo - a great review of papers.

Miscellaneous

Board to attach paper to (need to be able to lift and tilt, and should be big enough for your entire paper) - I like using a gesso board, but I have also used foam core and wood. You want something that wont bend and is non-porous.
Paper towels (smooth, not bumpy, i.e. Viva)
3 Hand towels (one for under your water, and one for setting your brushes on, and one for spills and emergencies)
Palette (John Pike or other) - John Pike Watercolor Palette
#2 Pencil
Plastic white eraser - Staedtler Mars Latex-Free Eraser, White, 1 Pack (STD52650)
Kneaded eraser - Large Grey Kneaded Eraser
Pencil sharpener
Containers to hold everything

Efficiency Supplies

Don't get the things in this section unless you really want them and are painting enough to justify them. You can get along fine without them.

Pipette or straw (transfer water)
Medium fine spray bottle (rewetting palette, wetting background)
Hair dryer (faster drying)
Tracing paper (capture designs)
Saral graphite transfer paper (copying images onto watercolor paper) - SARAL PAPER Saral Graphite 12" x12 Transfer Paper
Ballpoint pen (needed to use the transfer paper)
White artist tape 1" (painting borders, holding paper) - Pro Art 1-Inch by 60-Yards White Artist Tape
Masking fluid, small applicator (blocking off fine lines) - Fineline Masking Fluid Pen 20 Gauge W/Masking Fluid, 1.25 Ounces
Cheap nylon brush for masking fluid (blocking off areas)
Rubber masking fluid removal eraser (easier masking fluid removal) - XYRON 23675 Adhesive 2 Inch by 2 Inch Eraser
Ivory bar soap (prevents masking fluid from sticking to brush) - Ivory Original Bar Soap, 3.1 oz - 3 ea
Hotel key plastic card, cut lengthwise (scraping paint, wringing out brush)
Transparency film (finding good colors for half-finished paintings) - TruOffice Transparency Film for Laser Printers, Quantity 50 (TF-LP)
Dual-sided water container (I really like my Loew Cornell Brush Tub II, easy water-change, ridges inside for easy brush cleaning, mini palette lid, just don't ever set your brushes in the holes on the side) - Loew Cornell, Brush Tub II

Miscellaneous Supplies

Don't get the things in this section unless you really want them and are painting enough to justify them. You can get along fine without them.

Additional Brushes:
Water brushes (for travel/plein air) - Pentel Arts Aquash Water Brush Assorted Tips, Pack of 3 (FRHBFMBP3)
Fan brush (great for line texture) - Royal & Langnickel Series 4200 Mini-Majestic Brushes 12/0 fan
Cheap Joe's Lizard's Lick (great for really long thing lines) - Cheap Joe's Lizard's Lick Brushes
Loew-Cornell 270-3/8 Maxine's Mop (great for scrubbing/lifting) - Loew-Cornell 3/8-Inch 270 Maxine Thomas Mop Artist Brush, Goat Hair

Original Buddha Board (for stroke practice) - The Original Buddha Board: Relaxing Water Drawing, Painting & Writing Board with Bamboo Brush & Stand
Color wheel (There are many of these available as graphics free online. Specifically look for one that is the Munsell color wheel (5 primary colors), as opposed to Newton's red-yellow-blue.
Alvin rolling ruler (if you are doing a lot of architectural buildings, this could help speed up the process of transferring the drawing to your paper) - Alvin 312 Rolling Parallel Ruler, 12 Inch
Magic eraser sponge (This didn't seem to work any better than just using water and a sturdy paper towel.)
Bulldog clips 3 inches (securing paper to working board without tape, excellent for use with transfer paper) - This link sells them in a set of 12; you might be able to find a smaller quantity elsewhere. 4 of them is sufficient. - X-ACTO 4 Bulldog Clips, 3 Inches, Box of 12
Dotting tools (rounded tips, multiple sizes, for making small dots with masking fluid/paint/white gouche) - Valar Dohaeris Wooden Ball Stylus Dotting Tools Set Embossing Pattern Clay Sculpting Modeling Tools
Silicone paint scraper (grass and bark effects, don't get a hard plastic one that will damage the paper)
X-acto knife (precise paint removal) - X-ACTO 2 Knife With Safety Cap
Bone folding tool (for easier creases for tearing paper) - Fiskars Traditional Bone Folder
Tube wringer (get every last drop of paint) - Tube Wringer 202-N, Light Duty

Mediums:
Gum arabic (paint change for easier lifting, brush storage for keeping tips nice) - Winsor & Newton Gum Arabic, 75ml
Ox gall (paint change for more flow) - Winsor & Newton Water Color Medium Ox Gall Liquid, 75ml
QOR Light Dimensional Ground (watercolor-whiteout, effects) - QoR Watercolor Light Dimensional Ground 8 Oz

Effects Supplies

The things in this section are common household items. You wont need them until Lesson 4, but you can keep an eye out and build your collection as you work through the next lessons.

Table salt (star effect)
Rock salt (star effect)
Saran wrap (rocky effect)
Natural sponges (textures)
Makeup sponge (fine, shaped textures)
Kitchen sponge (texture)
Sugar (texture)
Dish soap (texture)
Bubble wrap (texture)
Straw (blown lines)
Desiccant (texture)
Toothbrush (splatter)
Splatter screen (fine splatter)
Corrugated cardboard (line-wood)
Sodium polyacrylate (sand effect, AKA diaper dust - cut open a clean diaper and shake out the white powder and collect it)
Q-tips (soft lift-off)

Can I Use Different [x]?

Short Answer:

Yes, but you may have difficulty with getting the same results as expected in the lesson.

Long Answer:

Paper

Paper is the most critical element in watercolor. Don't do watercolor on non-watercolor paper; it'll make the paper weep in despair and you'll know the paper is sad because it will bubble up and share its unhappiness with you.

Cheap watercolor paper... it depends. Say you want to create a perfect flower painting, so you practice a bunch on Canson. The paint and water flow a certain way. Despite this, you get to a point where you can do the perfect petal and you are happy with it, and then you go to put that perfect petal on Arches... and whoops. The paint spreads differently and your perfect petal doesn't come out as intended.

But then if we compare to making a fire with a bow drill or hand drill, you practice using cedar wood, because that wood is hard and very hard to make a fire with. If you can make a fire with cedar wood, you can pretty much use any of the common woods and get a fire. So you could practice on Canson for a while, to get the feel of the brush in your hand and the wetness of the brush and the thickness of the pigment on the brush, but then, before you swap to doing a "real" painting on Arches, you're going to have to practice a bit on Arches to get the feel for how the paper interacts with those qualities. You'll get a lovely flow on Arches that you wont get on Canson.

Cold press paper is bumpy. Hot press paper is smooth. The bumps make some dry brushing techniques like creating sparkles on water easier, while smooth paper makes straight/smooth-line edges much easier. Rough paper is super-bumpy. Use your personal preference. If you don't know, get cold press.

The less you spend on paper, the harder it will be to get expected watercolor effects, particularly paint-flow across the page into an already damp area, and sometimes the effects will even be impossible to do.

My note on super-cheap watercolor paper for kids (like Walmart brand): It might be good for tearing off a corner and chewing on it as a replacement for bubblegum (if you don't mind that it's probably toxic), but it is not good for watercolor.

Paint

You do not need the same colors or paints that are listed or shown here.

Paints have different binders and composition which means they will mix and flow across the paper differently from brand to brand and even within colors within a brand. If you already own watercolors, use those until you decide if they are limiting your watercolor growth and learning. If your paints are professional tube paints (regardless of brand), it will be easier to prepare differing consistencies. No matter which paints you have (the ones listed here, or your own colors), you will still need to play with them to see how much water you need for different effects and how they flow across the paper. There's no shortcut to experience knowledge, no matter how Neo in the movie The Matrix got his.

Brushes

If you already have brushes, use them until you decide they are limiting your watercolor growth and learning. You need a sharp-point one (details), a round-point one (general mixing/painting), and a large one (wetting large areas and doing backgrounds).