Gluten Free bulk-goods?
Are you wanting bulk for price, flexibility or price?
Best prices (but cross-contamination ? I am celiac and have been OK but many are scared:
White rice flour - Thai brands from Asian grocery
Besan - Indian grocery
All-purpose blends - Trader Joes and Costco (Bob's Red Mill). Costco also has almond meal.
Whole foods has best prices on Millet or Sorghum flour, and competitive for Xanthan and basic all-purpose blends, believe it or not. Safeway now carries a store brand all-purpose blend, and Nob Hill/Raleys often puts them on sale.
But honestly I usually order online. I watch Gilt for sales on Cup 4 Cup 25 lb. bags, use Amazon for other things in bulk.