I know you mean no disrespect, but actually the Gods are not businessmen. I'm saying that because you use the word "price" as if you're buying something. In fact as it says on JoS we offer things in return as a token of our gratitude, much like how we would give a gift to some friend who helped us. It's the same thing, the Gods actually don't demand anything, we offer help in return as a friendly gesture. And this is actually mentioned in JoS in the summoning page. If you read it carefully it has a paragraph about it giving examples there.
