Looking to improve your documentation photography on the cheap? Rather than buying a glitzy new camera, you might want to focus your effort on improving your lighting. And you don’t have to spent much money, either. Over at CRAFT, Brookelynn Morris has a nice write-up of the photography tools that she uses for her tutorial photos, which consists mostly of inexpensive lights and light modifiers.
Lighting doesn’t have to be complicated or fancy (just turn a couple of them on!), however if you are interested in learning about it, I would suggest checking out a copy of Light, Science and Magic.