Those instantly-foaming hand soaps are lovely, but extremely overpriced for what you're getting. Luckily, once your full-priced bottle runs out, you can make your own at a much lower cost. Here's how:
Pour one part generic brand hand soap (buying in bulk at a warehouse store makes it even cheaper!) into the empty foaming soap bottle.
Add three parts water to the soap dispenser.
Stir with a coffee stirrer or replace the cap and shake gently.
Enjoy! The average bottle of foaming hand soap costs at least $2.50; this recipe runs you about 50 cents, even less if you buy in bulk.