Cascade Surplus. 5 buck a piece.
Grab them while they can be bought.
http://www.cascadesurplus.com/catalog/i ... Path/71_81
I've been looking around for suitable chips to use for cache tag ram. Unfortunately, so far I have found them at around 9 USD a piece when you buy 100, (with a minimum order amount of 500 USD) which is a little bit too expensive since I don't think I'd be able to sell that many accelerators.