Do it yourself

I have a suggestion that i haven't seen here yet. I have seen sandboxes with a frame made of 6" PVC drain pipe, witha tarp that was about 3' bigger all around. This alowed the tarp to sag inside the frame, to be filled with sand, and still be anchored with plastic tent stakes around the outside of the frame. This sandbox is non- toxic, and easy to move if neccessary. Just wait until the glue drys, before putting it out for the kid(s) to play in. The tarp will need to be replaced about once a year, and you can poke holes in it for drainage if you want to keep it from becoming a pond :) You can also cover it with another tarp.