First off, I guess I'm frugal because instead of just practicing on a regular sheet of watercolor paper I have found I like cutting it into fourths. This way I don't feel bad about tossing a few of them in the trash. Chopping a sheet into fourths gives me smaller areas to paint as well. I'm not sure if this helps with dealing with warpage because they still tend to curl up but I can easily set them under a book or something once they are dry and they straighten out over night. I actually tapped one of them down on a thin piece of flooring board to see how that went. Worked pretty well, maybe I'll show that one in another thread.
I am not using a fancy paper, I bought an "Artist's Loft" watercolor pad - Cold press finish - Acid free - 12" x 9" x 25 sheets that I purchased at Michael's. I don't recall how much it was but at my level of experience with watercolor I wasn't going to fork out a bunch. I like the Cold Press because it's almost smooth and certainly much cheaper than the Hot press. I don't like the roughness (or I'm not used to it) of the standard Watercolor paper so Cold Press works for me.
I also picked up a cheapO pack of watercolor brushes also "Artist's Loft". I attempted using them and absolutely hated them. The hairs where coming out and making a mess of things. I quickly tossed them into a pile for use whenever I want to paint something with acid or something. I then went to a Jo Ann's (a type of hobby/craft store) and picked up a Koi Water Colorsocket Field Sketch Box - I love this thing. It has a synthetic brush that comes with it that has a water fillable handle so you have your water carried within the brush. I did get some extra paint but I haven't yet really needed it.
Recently, I splurged and bought a 25.00 Princeton Neptune #16 super soft brush. I love this thing as well. The experts all say if there is one thing you must get right, it's the brushes and I'm finding myself agreeing with them.
So that's my gear for now, let's get to it.
I begin with a little sketch of a subterranean area drawn in pencil: