Or you can get an ASIC miner from a team-mate for less than $50. Depends on what kind of power source you can provide and how much power you're willing to put into it.

1.6 GH/s Ant miners are easy to come by just by asking and are just like a little thumbdrive with a heat sink. No external power required.
There are still 33 GH/s Rock Miners up on offer around here I think that simply need either a Molex to barrel power adapter, or a standalone power supply.
Pretty sure there are others that might be available around here as well.