I live in my kitchen, so I can go through a bottle of hand soap a week. I prefer the foaming kind, so I make my own. Many people know that the thing that makes it foaming is the bottle, so this is a way to save you old bottles instead of just throwing them out.
Dish Soap (any kind)
Empty Foaming Hand Soap Bottle
-Pour about 1 inch of dish soap in the bottle. Top with water, and you are ready to go.