I have this 4-core
AMD Phenom II x4 960T sitting here doing nothing. This is the one that can unlock to 6-cores (and this particular one does) so it'll run pretty much any game with no problem, especially ones that love additional cores like BF3. Rated at 95W TDP, but you can disable cores through BIOS down to 1 core and have identical power draw as a Sempron 145 (confirmed through Kill-A-Watt meter). Comes with factory heat sink fan (aluminum). $100 in BTC or LTC shipped within the US.
I also have a Corsair AX1200 for sale. Solid and reliable. This is one of the best PSUs available!! $210 in BTC or LTC shipped within the US.