Mix 3 parts water and 1 part soap or shampoo into an old foam soap dispenser. Shake well. Then you’ve got a whole new bottle of foam soap or shampoo! Yahooooo!
For some reason, I feel like the foam soap and shampoo go farther than the regular stuff. When B’s foam shampoo ran out I mixed 3 parts water and 1 part baby shampoo for N. It worked! Just a small amount of the shampoo turned into a whole bottle.