You're probably familiar with Whole Foods Market; it's a national chain specializing in organic, fresh, local and dietary-restricted items. The nearest one to us is in the Quarry Market a couple of miles away.
They have the largest selection of gluten free products in San Antonio- fresh, prepared, frozen or packaged. Most, but not all, will have a purple shelf tag to help you locate them. (One aisle, in fact, has a 20 foot long strip of purple tape on the floor in front of the GF section.)
Whole Foods carries several GF beers, including Redbridge, Bard's Tale and Greens.
You just need to be careful in the Bakery Department, Deli and at the salad bar- read the labels and remember that for salad and food bars, cross-contamination cannot be ruled out. Some people have reported good results when they buy a Whole Foods GF Bakehouse frozen pizza crust and then take it over to the bakery to choose toppings and have it baked. Now that's "full service!"