Depends on the auction. There's some for the Grammy's Foundation, some of the ones that are from award ceremonies or movie props go to film ones. Haven't spotted one that's for Madonna's charity though.
That 'Healthy' t-shirt is such an amazing item, I can't believe it's not been snapped up already. Some of you may not realize, it is one of the most recognizable items from her wardrobe. This is such an important item of pop clothing I hope it doesn't disappear into a collection.