I found them at my local Long's Drugs (in Redwood City CA). They were near the 'sports nutrition' section of the store, in a separate cardboard display that I bumped into ( that's how I found them ). Best of all, they were 79 cents a bag !

Longs is a drugstore chain in the western US. No idea if all the Long's stores would carry them, or if it was only a local promotion.