Share 'best disc storage box'

I am wondering if anyone knows what sort of box or bin is best for storing discs. My ideal criteria: affordable, each holding approx. 25-30 discs in each container and heat resistant(ie. want to be able to keep them in the back of my station wagon during summer without warping). any thoughts. Last year I just used cardboard boxes that I covered with several towels to keep the sun off them. any th…