You could cut open a tennis ball and fill it. Then you would have some round ones. Just be sure to make a flat spot so you will have a flat surface to set your pots on. I have also cut down the large margarine bowls into varying heights and filled them (with a hole down the middle for pot drainage) to use as pedestals.

I use the 4 and 6 pack plastic plant cells to make feet for pots and troughs. The tennis bowl idea sounds great.

Why not use leaves, like others have used giant leaves for fountains, but use smaller leaves in the same manner. Just a thought. I have wondered how this would work myself.? Good Luck let me know if it works. Puppy3

i need to get hypertufa out of the "just an idea" phase, and into reality! thanks for the suggestions! -freezing in Cleveland

I go to a party supplies store and pick up cheap plastic dishes. I've used deviled egg trays of various sizes, bowls and candy dishes. My favorite is a small clam shell shaped candy dish that costs $.99. I can use them quite a few times before they give out. The dish is deep enough for decent pot feet and the clam shell effect is very nice peeking out from under a pot.
Have you browsed the dollar stores for ideas?

I just bought a new gas range, and am using the grids from the burners of the old stove, for my pot stands- 4 for free.

How about cutting the bottoms off soft drink plastic bottles and filling them with cement?

I save all the plastic containers that come in cookies and candies now. They work great