So I can't give much insight into breeding costs as I'm a new owner of one lil snake, but I can link you to SDA's post on here about a conditioning experiment he's been working on with his BP. It's a very interesting read and seems to fit in with your project concerning snake domestication.

Here's the thread, I'm going to be following this one as well because I'm also quite interested in the basic costs of running a breeding project. I'd like to get into it myself one day and having some general figures to consider would be amazing

Good luck with your research!