This is the best selection of Mexican and Latin American goods that I could find around Dane County. Not only do they have all the frijoles and hot sauces I could need, but the staff is very friendly and knowledgeable. When I lived downtown, I'd head all the way out to Monona so that I could be guaranteed a fine selection of ripe avocados.
As far as cost is concerned, I suppose it all depends on how hungry you are. It is, after all, a grocery store.