As you may know from my June entry, I use body wash instead of bar soap, so while the following idea may seem basic, when I heard it, my eyes opened.
A family friend who got tired of trying to deal with the little pieces that remain of a soap bar near the end of its lifetime decided to buy a luffa with a soap pocket. That way, the entire bar of soap is used before a new one is needed.
I love the idea of getting the most out of every product. It saves money and resources.