How can I collect a fee without getting into legal trouble?

[Eva Suzuki]

Hello everyone, 

I responded to requests where wholesalers were looking for particular deals. I found them and contacted the seller. I was very upfront with the seller and he said fine about referring his deals to buyers but stated I should collect my fee from the buyer.  I have questions, 1. How can I do this? 2. Will I get into legal trouble doing this? 3.The seller said he got the deals at auction and he owns the contract.  What the heck does this mean?

Thank you everyone!