If you are talking about just breaking even on the keeping of snakes, that is very doable. The key to that is breeding your own feeders, and selling extras.
Right now my entire collection is "free" to keep because of my feeder production. I produce enough feeders to feed my entire collection, and have enough left over to sell to cover the costs of the rat feed and bedding.
Considering I use newspaper for substrate for my snakes, there are no other costs... except for electricity and water.