I really like doing work for friends and family. I often either charge very little or ask for small favors in return; I call this payment in kind. As an example, I recently painted the side of a friends house and in return for my labor he performed a service on my car. If you can do it sustainably, it's a great way to get by in life. Although it's quite clear that money can corrupt friendship, I do think that it's important for a service to be rewarded. Maybe payments in kind represent a less corrupting way of rewarding a service.
RE: The monetary boundaries of friendship?