OP, you can also check out Seuntjie' DiceBot. It is free and open source, and has been around since 2013, if I'm not mistaken. It works with most dice gambling websites.
I was going to suggest him this one. But, Since you already suggested. I would say I agree with you. I don't see any reason to buy the Premium dice bot or whatever script people selling out there. In long run, House always wins. Making money with whatever bot is not guaranteed. So, better try Seuntjie's DiceBot for free. You can log in using API. Most of the popular dice sites are already listed on their software.