Low lipped glass ashtrays work good, too. I bought a couple really cheap at a second hand store. I've bought quite a few nice ceramic low lipped bowls at Goodwill for between .49 and .99.
Nice, i stopped by target's and in their $1.00 section was some cute divided kids plates. I put the pellets on one side and the vegs on the other. They can even climb them without knocking them over.