After talking to folks I know with more experience in this than I have, here's the base cost for commissioning a custom piece of art from me:
Rough sketch = $5
Pencils only, cleaned up = $15
Inked = $20 for black ink, $25 for coloured ink
Fully coloured = $35
The prices are slightly negotiable, but not TOO negotiable; these are on the low end of what most other artists charge, and I don't want to undercut them too much and piss them off
Right now, anything I do in full colour is going to be with coloured pencils; I'm going to teach myself how to do it digitally, but at the moment, the quality of a digitally-coloured picture would be much lower than what I can do with pencils and would take a lot longer. However, someday I WILL offer both digital and analogue options for colour.
Here's a list, though not necessarily exhaustive, of subjects I enjoy drawing and can guarantee my standard level of quality on: Elfquest, Record of Lodoss War, Slayers, animals, Mass Effect, Pirates of Dark Water, Weiss Kreuz, Teen Titans (comic or cartoon), Shamanic Princess, Utena, Soul Calibur series, Legacy of Kain, Legend of Zelda, Noir, Evangelion, just about anything by Rumiko Takahashi, Fushigi Yuugi and Ayashi no Ceres, Dragon Half, Magic Knight Rayearth, Lord of the Rings, anything by Hayao Miyazaki, Ruin Explorers, Wheel of Time, Xanth series, Orphen, Neverwinter Nights/Dungeons & Dragons in general, Gauntlet Legends/Dark Legacy, World of Warcraft, Morrowind/Oblivion (haven't played Skyrim yet, but it's set in the same world), King's Field, Sailormoon, Wedding Peach, Cardcaptor Sakura, Avatar (James Cameron, not the cartoon), Cowboy Bebop, Outlaw Star, Gall Force, Phantasy Star series, Lost Universe, Farscape, Dune, Darkover, Gundam Wing, Firefly, Buffy/Angel, Macross, Vandread, Thundercats, and Silverhawks.
As I mentioned before, I won't draw porn, but PDAs and canoodling are okay. Just don't expect me to make them softcore or anything.