Does anybody have any experience with wholesale companies in Dayton, OH. My main question is if there is a maximum fee they can charge you for assigning the interest in there contract over to you.

I have done Wholsaling myself as well as done business with others. The answer to your question is no. There are no rules that limit what someone can sell their equitable interest for just like you selling your car for example. If you want to sell a 2005 F150 with 300k miles on it for $80 you can do it if someone is willing to pay that amount. This situation is the same... you don’t have to pay their asking price but they can ask for it or sell to someone who will pay it potentially. 
my advice is don’t be concerned with how much they are making. All you should care about is how good/ bad is the deal FOR YOU at that price 

@Ozzy Smith thank you so much for the help!

Happy to help @David Uzhca . Remember focus on what you want, and don’t worry about what others have or do Bc at the end of the day you can only control you.