I'd never heard of this. I went to my doctor this morning and he was sending a prescription for me to Walgreens. I always ask for the generic if available, since my insurance will pay the max. I usually end up with a $10 co-payment. He said to me, "Let me check, I think this is on the $4 list from Walmart. It was. I can also get it set up they mail to me every month. Pretty cool. http://www.walmart.com/catalog/catalog.gsp?cat=546834 You'll find a list of all the prescriptions available for $4, listed by 'condition treated.'