Wholesaling finder

[Eldar M.]

Dear BP members.  First I would like to thank all the members, organizers, developers and contributors that bettering this "Gold Mind" named @BiggerPockets. Kudos to @Joshua Dorkin and @Brandon Turner  that make the Podcast better and better episode after episode.

I am trying to bring a potential buyer to a deal that I got from another wholesaler. I just don't know how to create a contract between the potential buyer and myself, to get a fee for my service.  I have contacted the wholesaler and he said that I should add my fee to the purchase price.

Do I need to have a contract with my potential buyer?

If so, what kind of contract?

What's the average fee that one can charge in CA (California, Los Angeles county) for finding an off-market deal?

And, are there any legal issues, grey zones in transaction as such?

Thank you for taking the time to read and respond!