Finders fee?!? How much is right?

[Tom Port]

Hi all, 

Long story short, I've been working with a advisor that is deeply connected to an area that I am seeking to buy property in. We work together on a side project, and he's mentioned that he would be happy to pass on any off market deals that he can't fund himself. I want to make sure I receive those deals therefore, I was going to suggest that I'd pay a finders fee on any deals I close on. 

My question is what is the right number? I'd prefer a flat fee as opposed to a percentage, the properties I am looking to buy are in the circa 300k range! 

Thank you for any suggestions!