I used a 24x36 shelf set from home depot, each shelf will hold two 28qt sterilite tubs side by side, it comes with 5 shelves but I am only using 3 for now. I put 1/4" white melemine on the bottom and top of each shelf. The shelves are vented so I wanted to help prevent heat loss that's why I put it on the bottom. The shelves are 50 a set and can do 8 tubs total. It would take two shwets of melemine for a whole set. So 80 bucks is about as cheap as I could figure out for making it. Also target had the 28qt tubs on sale for 4.50 each.
I only have 3 snakes in it now but ready to expand as needed.
The tank on top has a 4ft columbian rainbow boa.