Bird Dog Promissory Note or Contract Question

[Jenna Gainey]

An investor out of my area reached out to me after seeing my AD on Craigs list about wholesaling and bird dogging . He is looking for a property in a particular region to flip. I finally found a deal . In our first discussion he communicated that he prefer to pay us a "finders fee" instead of wholesale. (I am okay with that in this particular instance as the property is REO and wholesaling with banks is not my niche quite yet). My worry is that we pass the property to him and he never pay the finders fee verbally agreed upon. My question is: Does anyone have an example of a promissory not or contract that would bind this agreement?