I bought one of the cheap pools that has an inflatable top ring. You
fill it with water and it stands up by itself. Drawback is you need a
level spot to put it up.

I put mine on the levelest spot I could find and filled it up. The
compacting of the soil and the uneveness caused it to lean after two
weeks. I drained it and moved and I am now going to level the spot
with sand.

Do I need a ring of some sort to hold back the sand or can I just level
it out and put the pool on top. The sand will be about 3" thick on the
'low' side.