Gear to get started

I tried the wiki link but that doesn't seem to go anywhere

Id like to get started with reproducing motorcycle and car parts for my classic vehicles

Early research suggests a DSLR with at least 18mp and a fixed prime lens.

Whats a good bang for buck DSLR for under $400 in the used market I can use to get started and last me for a couple of years ?

And free software that could get me some decent results .