My son just bought an used dual core android phone for T-mobile (peer pressure, single core smart phone doesn't cut it anymore). He spent slightly over $200 of his money (50% of his net worth). He said this was the cheapest you can get. New ones run over $300. I asked him what if you brick it? He said, no way (he just bricked one of his previous phones).
BTW: HTC Sensation 4G