We've only had weekend sitters for our cat so far (apart from family, who gladly do it for free), and we've asked local kids, and paid them a small amount, about the price of a movie ticket. Had we asked the parents we would have asked just as a favour, but it seems like a good "small job" to hire kids for.
My gut feeling says go with a favour back, or giftcards, wine bottle or similar. The more you appreciate it and need it, the more personal.
Funny - I'm just now reading a fascinating book about how and why people act irrationally in a predictable manner in many situations, and one of the authors points is the difference between social norms (doing things for the warm fuzzies) and market norms (doing things for money).
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett