What exactly this script does? just click on spin button? ~$10 for a script that only clicks on spin button(and for a site that doesn't pay/is scam), that's very expensive! if i were to automate the clicking i'd go with imacros, it's easy, simple and free!
You are right, we do not know the site is paying or not so it would be risky to buy this script so yeah imacros would be the best option if someone want to run auto spin in this shady site. I doubt the site is legit, so dont buy the script unless there are payment proofs from the site.