Wal-Mart aka Wally World.
I think I bought four for 8.00 or 9.00 bucks. It makes a big difference when passing. Hardly no bending and stretching. I recently had my carpets cleaned and the guy that did it gave me all these furniture pads to place on the bottom of my furniture legs. I saw them and had a great idea. I have yet to use them. They are a hardened styrafoam. PERFECT! I'll let you know how they work.