Moeller Arms had Spike's lowers last time I was there. Thinking the price was around $125? Good quality ones. While they are cheaper online, remember you have to throw in shipping and the transfer fee.
I bought mine, a YHM, from Exeter Arms at one of the fun shows back in '09. Looked into getting one from some local shops, most didn't have them or were price gouging pretty bad (Bullet Hole) at the time.