You shouldn't use MDF though, If it gets wet it is nasty and it tends to bow. Plus it is so freaking heavy!!!
I would go pick up a few tubs and a few heat pads and dimmers for now. That way you can at least set them up to be by themselves. You could just stack the tubs on top of eachother like a rack (but with no wood base obviously). That should only cost you about $50. Borrow it if you have to. You shouldn't be caring for you snakes when it is convenient for you.