WalMart (whatever you may think of them) has just expanded this program to include 49 states. My state is now offering this and I can't tell you what a relief it is!
You can get a printable list of the generics which are available for $4 at this link. Not all drugs are available and you must get the generic version in order to qualify, but I was already doing that at my other pharmacy simply because they are cheaper than the name brand. I believe Target stores and HEB are also following suit.
This program is very good news for people in the U.S., where, IMHO, we have a sad lack of affordable health care for the poor, the elderly and the indigent.