Does anyone know where I could buy some cpu's on the AM3 socket?
Not AM3+ though.
They might sell at newegg online. Otherwise, AM3 is outdated
You can go as far back as AM2 cpu's. They will work all the way up to AM3+. AM2, AM2+ will work in a AM3 mobo. Try E-bay.
You have this backwards. AM3 CPUs will work on some AM2 and most AM2+ boards because AM3 CPU's support both DDR2 and DDR3 RAM, but an AM2 CPU will not work on an AM3 motherboard, as AM3 is DDR3 only and no AM2/+ CPU's have DDR3 memory controllers.