I only took money a few times when helping people. I used my Jeep to pull a few people out of bad spots. They asked what I wanted, and I said nothing, but they could make a donation(basically membership fee) to the state wide 4wd club I was in. It was an important charity to me, since they fought to keep trails open, lobbied for then new "Tread lightly" program, and did other conservation projects. The price for the membership was really low, like $10.
Some did it, some didn't. I just gave them the envelope and form, hoping they would, but never expecting they would.
It is kinda funny, 'cause I had joined the club when someone else had pulled me out. I offered them some money, but instead they asked me to send it to thier charity, which was the 4wd club.