Even at $50 USD it doesn't make sense to buy these except for the novelty. If you use the calculator below, you'll see that you will never even break even. According to this calculator you are going to have to get a device that has more hashing power or get these for less than $10 USD. I'm scared the fever over ASICs will get folks in so upside down that they'll get a sour taste for BTC and bail on the currency altogether....seen it happen before.

http://mining.thegenesisblock.com/