The Body Shop's are $5 and the store always has sales) but they allow you to use your own body wash to exfoliate. No loofah to drop, no scrub to wash down the drain and by the time you use these for a few weeks, your cost per use is nearly nothing.
I always have a pair of these around. Right now, my hands can be seen sporting a green pair that I picked up at one of their semi-annual sales. Somehow I find these less germy than bath poofs or loofahs since you can get the insides real good with water before hanging them up to dry. If you haven't been able to find a scrub you love, give these guys a try.