I made two five tub adult snake racks for just less then $200. I could buy the same thing for $700 so yes, it is much cheaper. It is pretty easy.
Here a some youtube examples
https://www.youtube.com/watch?v=DLDxk2yp2Vs
https://www.youtube.com/watch?v=vsKPanLaSHA
https://www.youtube.com/watch?v=2gXGS1ZAcS4
There is a lot more instructions. The hardest part about building a snake rack is to making the exact measurements and cuts. If they are off, you will need to make adjustments which can be a little annoying. It is easier to buy, but cheaper to make.