i found these sterilite drawer units at walmart and decided that they would make a much cheaper alternative to purchasing racks for my growing leopard gecko colony. i purchased two different sizes, one for groups of adults and one for individual adults and/or groups of juvies. they were about $6-8 each, so figure however many you need plus heat tape and that's it!
(i don't recommend these drawers for snakes. while i do feel that they are secure enough for terrestrial geckos such as leos i do not believe they would make a secure enclosure for a ball python or any other type of snake.)
drawer units in the 2 different sizes that i purchased:
heat tape installed down one side of the bottom of each drawer:
slot in the back of each drawer for heat tape connectors: