Before you turn it down. I would investigate. Go to the track as a spectator. Look what he is selling and who is buying. Not sure if you want to do people photography or not. But having a nice big sign up that says "Official Track Photographer" And your information. And available for xxxxx or xxxx events. Just may give you the extra work that will pay better! If you don't make money. Keep track and write it off. But you still get the free advertising that just may kick in some good work.