I buy whatever they sell at the local Pet Supplies Plus - it comes in a box with 5 pouches. It's the only thing you can find around here, so I won't be much help as far as that's concerned.
I had a shallow ceramic dish and that's what I put it in. You're right - they'll trash the plastic things and with this thing, they can both get into it at the same time, which we enjoy watching - not sure if they enjoy bathing together, though! They tend to get snippy with each other any time there's something special to do.
As for leaving it in the cage, I wouldn't suggest it. They will trash the sand and you won't be able to use it again. They end up using it as a litter box and my one goo even hides treats in there, which combined with the litter box thing, just grosses me out!! Everywhere I've read, they suggest putting it in the cage for about 10 minutes and removing it.
Kelly, A Mom First to:
Madalyn, 11 years old
Helayna, 3 years old
No names, don't come when I call
Bullet and Molasses