Having nice customers that don't want to pay a fair rate always sucks. It makes me mutter under my breath. You have to deal with that before it really bugs you. Try this: tell the customer that you charge a surcharge for policing dog dung. You consider golf balls to be just as much of a problem and just as time consuming. You didn't want to charge him more, so you had just been using the balls for the trouble and time spent on policing them. If he would like to keep them from now on you can begin charging the $15 dollar fee for the time spent. You just may get the $40 you'd like. And what the hell does "give back to the golfers" mean? That's love.