I wouldn't pay $1 for it.
Power supplies are one of the components in your computer that you REALLY shouldn't cheap out on. Cheap case? No problem. Cheap memory? Ok. Cheap CPU Cooler? No problem.
The power supply is responsible for taking power out of the wall and converting it into something your computer can use. One little screw up can have catastrophic results. Generally speaking, if a stick of memory fails, your computer just starts to act funny or fail to POST. If your PSU fails, it can lead to sparks, smoke, fire, other dead components due to over-voltage, etc.
Buy something that is known to be good. You don't have to spend a TON, but $50 in decent PSU like a Corsair, Antec, Seasonic, etc. can mean $200 less you'll need to spend replacing your dead power supply, motherboard, and processor later on.