So I ordered an ARS rack a couple weeks ago, apparently they are moving to a new location and the shipping has been delayed for weeks. But in the mean time I purchased a collection of ball pythons from another snake keeper and needed some place to put 12 snakes, just temporarily until my rack comes in.
So I picked up these 28 quart tubs from Home Depot and drilled four 7/8 holes in each end for ventilation, then added coconut husk substrate. All together, even with the substate, it's less than $100! (The bins were less than $6 each) Of course there's no hotspot but I'll just keep it in the snake room at 82F until my rack comes in.
I'm going to stack them four high and put them on a wire shelving unit just to get them out of the way. This will be a good expandable system for any overflow I have now and then, and it all stacks together and can be put away in a very small space. I got the idea from an old BHB video, they had shoebox size bins with lids stacked on wire shelving units to hold all of their hatchlings. Of course once you sell a few snakes you can use that snake money to buy a rack or two for the rest. But in this case these will all be adult breeders.