Stop in for a cup of coffee

So a 600 dollar computer MAY net your 1200 a year?
Well, if you crack a block, you get 25 coins, but the odds are poor. Apparently miners pool their resources and split the blocks.

Every four years the return is halved. This just happened recently so for the next four years you get 25 coins per block then it drops to 12.5 or so.