Sand really isn't recommended for corn snakes. Ideally, you should switch over to aspen bedding. Sand can cause impaction and can dry the snake out too much, which causes shedding problems. Aspen bedding is preferred because pine and cedar release oils that can make the snake sick or even kill it. Cedar really shouldn't be used for anything except furniture. Some people use Eco Earth, which is coconut husks and is very nice to look at. It's relatively cheap, but the cheapest is aspen. You can get shredded aspen at feed stores for a few dollars. Pet stores are usually really expensive and you don't get as much for your money.