Ball pythons are a good investment, but things to think about,
1.will they breed?
2.what if they die?
3.can you afford a 200-500$ vet bill if somthing goes wrong?
4.Can you manage feeding all of them mice or rats weekly?
5.Can you also offord a rack for all of them?

Ball pythons are very beautiful animals and can be expensive but can be hard to sell at times. Hope this helped =D

-Payson