I made my DIY rack for less than $100. I got the multipurpose rack from Walmart, the tubs from Walmart, Flexwatt from a local reptile shop, Johnsons thermostat from reptilesbasics.com (not included in the price...thermostat alone is $80), wooden boards for each shelf at Home Depot, and then some binder clips.
There is now a 4th tub on top too, and Walmart sells the shelves separately so you can add more if you wanted to
will these tubs last them for their whole lives?
Reptiles
0.0.1 - Rhacodactylus Ciliatus, Cheerio
Mammals
1.1 - Canis Lupus Familiaris, Little Man & Molly