So i get that people buy bigger rigs for faster production, but say I put some old junker on as a miner. it ever get coins or do the "real" miners get all the coins?
If you join a mining pool, like Slush or Deepbit, you will still get a tiny revenue. On a regular computer (with none of that GPU/FPGA/ASIC stuff), you get 0.7-1.5 MHashes per second. You'd get about 0.000007 BTC (just an estimate) every few hours.