It can be a very simple agreement simply indicating that if the broker sells a home to a buyer you introduce him/her to, the broker will pay you whatever the amount is--the whole thing can be as short as 1 - 3 paragraphs, stated in plain english. Simply figure out what the agreement is--exactly--and then spell it out--exactly; make sure you also spell out when you will be paid and how (e.g. by money order; by check; etc.); what happens if the buyer ends up not going through with the sale; and whether you are entitled to any attorneys fees or other costs if you need to take legal action against the broker to enforce it.