If you want cheap, get a hard-tail with v-brakes. If you buy cheap disc brakes and cheap suspension, you are just getting junk. You'll get a much better bike for your money if you drop the parts that are only good when you pay for quality.

If you go the hard-tail route, you could eventually add on a cane-creek thud-buster seat post if you just want a little extra shock absorption on pavement and gravel. They aren't cheap, but they are a much better approach than a cheap rear shock in my opinion.