Next time you go, ask at the manager's desk for their
Gluten Free Shopping List, which is a handy reference of all the GF items they sell. (Well, current at the time of printing, anyway.)
The nice thing about the store is that many GF items are clearly marked on the shelves as well as on the packaging. And whereas the average store may only carry one or two products from a company that makes GF foods, Whole Foods will often carry most of the product line. (Annie's Naturals dressings, for example.)
But you're right about the $$$ issue. You almost need to bring someone with you to drag you out when the time comes. It's easy to go wild.