Cheapest? a 65+ quart Rubbermaid box with a human heating pad, a heatlamp, water dish, hidebox and some newspaper as substrate, plus thermometer and hydration meter to make sure that the heat and humidity levels are in the right range.
There's lots of other stuff you can use for your cage, but this is probably the absolute cheapest you can get in terms of BP enclosures.
0.1 Ball -Ruby-
0.1 Viper Boa -Vash-
....and lots and lots of feeder mousies.....
i have a heat lamp a human heat pad a water dish a hide box and substrate i just want to know how big i can get for the rubbermaid and wire mesh. i have 30 dollars.
yes it is, and $30 should be plenty for the stuff to make it too.
keep in mind though that you need 2 hides--one for the warm side and one for the cool side. just use a cereal box or something like that for the second hide if you don't already have one. and also you absolutely need to get an acurite digital thermometer/hygrometer from walmart to measure your temps and humidity. really, it is a necessity. it is $15, but you should be able to buy a good size rubbermaid or sterilte for $10 which still leaves you $5 for the screen and wire ties.