When you buy foaming soap you're paying for a lot of water and a foaming pump. So, if you've already purchased the pump, you may as well use it again (and again), by mixing foaming soap at home.
Step one, decide what kind of soap you'll be making. I make both hand soap and dish soap (think Dawn Direct Foam). After that, you need to get your hands on a foam pump. You can buy these through Pampered Chef or online, but I'd just buy a bottle of foam soap at the store and save the bottle. Or ask a friend for one, if it was just headed for the recycling bin.
Next, it just comes down to proportions.
Start with one part liquid soap to about five parts water, and adjust until you get the consistency you like. Hand soap is a little more forgiving than dish soap. The best part is that you can use up all kinds of liquid soap leftovers. Bubble bath works great, as does any body wash that does not have any "bits" in it. You can also add soap scents to mix it up. I personally like to use a bit of Soft Soap style hand soap and a squirt of bubble bath.
This can get a little tricky, and will depend on what brand you use, as some are more concentrated. I use Palmolive, and put 1/2 ounce of soap with 12 ounces of water. If you use too much, the soap will clog the pump. Too little and it won't have any cleaning power. The dish soap is great for when you have just one dish you need to wash (for me, that's when I discover the pan I need to make dinner is dirty) and you don't want to use a lot of soap or water. Of course, you can use dish soap to make hand soap, too. In fact, it smells really nice and cleans well!
Once you've mastered your perfect proportions, use a marker to note how high to fill the soap. That way, you don't need to measure every time.
I'm sure you can guess why this project is MSG, but I'll give you the rundown anyway.
-Reduced packaging by not buying all those pumps
-Lessen the carbon footprint of your soap (imagine truckloads of single-use bottles of foam soap traveling across the country, and smile as you refill your bottle)
-Saves LOTS of money
-Use up small portions of soap that might otherwise go wasted
-Less trips to the store to buy soap = less temptation to consume
Pretty significant impact for one quick project!