Minolta MD/MC (like Canon FD/FL) are not usable on dSLR/dSLT bodies without an adapter with an optical element in it to act like a short teleconverter so you can achieve focus to infinity. And a cheap one will be likely to have cheap glass, and can reduce image quality. A simple ring adapter will limit the focus capability of the lens to less than infinity, and could be useful for a macro or portrait lens. But overall, adapting MD/MC to dSLR/dSLT bodies is problematic.

The reason is because the distance the lens has to be held from the image plane is specific to the mount system and for achieving the full focus range. Holding the lens farther out from the body is like using a macro extension tube. MD/MC's "registration distance" is shallower than all the dSLR/dSLT mounts that are current. And an adapter ring adds distance. It's easy to adapter a deeper mount to a shallower one, but adapting a shallower one to a deeper one requires shaving some distance off the camera mount or the back of the lens mount. It can be done, but it's not for the faint of heart. The only easy MD/MC adaption to dSLR that I know of is getting a Rokkor 58mm f/1.2 onto Canon EOS with a Leitax lens mount replacement kit.

Mirrorless cameras, however, have much shallower registration distances than dSLR/dSLT mounts. So all the mirrorless mounts: micro four-thirds, Sony E, Fuji X, etc. can use simple ring adapters with Minolta MD/MC lenses. But be aware that the crop factor is liable to cause a few issues, here. MD/MC are manual focus film lenses, so it's unlikely you'll find anything wider than 28mm at affordable prices. And on a 1.5x or 2x crop sensor, 28mm isn't particularly wide any more. There's also the fact that mirrorless cameras tend to be small, and SLR lenses can be large. Many mirrorless adapters tend to prefer rangefinder glass--if they can find/afford it.

You also, of course, lose autofocus, aperture control from the body (i.e., you can only shoot in full manual or aperture priority modes), and EXIF information from the lens, since these lenses have no electronic communication to speak of.