The may not be new to you, but
it was a lesson for me today!
I purchased one of those foaming hand soap dispensers a few weeks ago (of course with a coupon). It was covered in a cute plastic wrapper so I could not see inside but when I was at the store I noticed another one that was in a see through bottle. I was shocked to see it was almost water! I thought I bet I can make my own solution. Having two boys and often two nephews we use a lot of hand soap. I purchased a large bottle of liquid hand soap and mixed it about 80/20 mixture. 80% water 20% soap and it worked!
It made hand soap for a whole lot less money!