WalMart has the good 41qt sterilite tubs, but Target has the clearview tubs that are easy to see through and have flatter bottoms. The 15qt tubs at Target run $3.99 when not on sale, I think. The 32qt tubs run $6.99 when not on sale. The 41qts at WalMart run $6-something.

Office Max or similar should have the Iris tubs, which are the flattest on the bottom and the most transparent. They are high though, and can be found cheaper at www.reptiletubs.com