Okay this is probably overdone...but! I have a good one for ya.
So you've already read that to save some money, you should buy refills. Yes that is true and I completely agree. You can find many household and body care items that are in refill packs at a reduced price.
Hand soap is even one of those items. But what type do you get? Say you buy the fancy foaming soap and then you want to get the refill? But OOPS! you bought regular soap!!! Oh noes! (lol) well to me, you bought the more economical one. "But mine's a foaming one and the regular soap won't work," you say...well don't go back to the store just yet. All you need to do is fill your container with about a third of the regular soap refill + water...yes water. Then give it a quick shake and test her out. It works! Woot! and you still have more of the soap left meaning you saved on your next refill! The only "problem" with this method is the occasional buildup of soap around the spout..but just clean that up and it's good as new. So not really a problem ;)