Generally about $20-$30 a couple of times a week (but that's for two of us, not as bad as it sounds), plus long-term staples. I'll spend on the order of $100 at the bulk food store every 4-6 months (again, not as bad as it sounds, because a lot of that ends up being snacks or spices), and maybe $20 every couple of weeks at the smaller bulk store. We spend about $40 every couple of weeks at the farmer's market for veggies. The bulk food purchases includes beans, lentils, flours and grains. Grocery doesn't include very much in the way of beans because I generally cook from dried rather than canned (slow cookers are your friend).
That works out to $95/week, and I know we don't blow the budget like that ever. The numbers I posted are the high end, and I'm probably overestimating how often we go shopping. (i.e. if I go shopping twice in the week I'll probably spend $18-$27 each time, but it's more likely to be twice in 9 days than in a week).