I own 5 running stores. I would recruit you to be on our Racing Team. The racing team is pure grassroots, word of mouth. For example, by having you on the team, that is one less local elite that is not racing for the competition. Also, you joining the team may mean I am able to coach you, thus I continue to gain more runners under my tutelage. As of this year, I have taken 7 4hr+ marathoners (women) and they are all under 3:15, with two under 3hrs.
This just builds credibility. I don't offer a discount for product to "A" team members, they get product for free, whichever brand they want. The sales reps are glad to provide the comp product. I also offer $1,000 stiped to travel for the best of the best on my racing team.
How do I determine ROI? I can't. I do know they bring in 1-5 customers per quarter based on influence, but it does not offset the "sponsorship", but I don't really care. I want guys like you to run fast for as long as possible. Just keep it going like I did, until life takes over, and then you still try to keep it going.
Best wishes.