I see you're from NYC, but have you ever been out to Fire Island? As expensive as it is, it is pretty casual and low key - not a spa/resort getaway that would get five star hotels. Most of the lodgings are summer rentals and there are very few hotels or b&bs.

My suggestion would be to find out if someone is renting out their place for a week. The Pines is a bit more male/wealthier. Cherry Grove is more casual/inclusive. If you want to be pampered, Fire Island is probably not the place. If you want to relax, lie on the beach, read, drink a little, then it is a great place to do that.