Get what you like or what you want to produce for your own collection. Honestly, making back even your initial investments (snakes, racks, food, supplies etc...) will take some time, if it happens at all.
I decided to get into ball pythons back in '05. This is my first breeding season, I hope to have anywhere from 1-6 clutches. Over the past 3 years, I have spend between $12-15,000. I do not expect to make that back money wise, which I am ok with as I knew that going into this. It does allow me to create combos that I would like to have in my collection, even if some of them might take me 10 years!