Oh, I was at a restaurant with my sister once, when she whipped out a little metal S-hook thingie from her purse. She hung one end onto the edge of the table, and the other held her purse. Looked way too fashionable for her to have bought it at Sears, though. If you want, I can ask her where she got it.
I think you get one free at Macy's from Elizabeth Arden when you spend $150 or more on makeup and feminine hygiene products.