I work as a part-time freelancer, devoting 15-20 hrs per week for this activity. It's 7 days a week though and my working hours are fexible. The rate is generally $5-$8/hr. I prefer fixed-price projects with payments for predefined miestones, rather than time-tracking.
I always do my best to keep an employer informed about the work progress and to make sure that the customer gets exactly what he expects. I only expect to be paid if the customer fully accepts the work. I do not require compensation for the partially done job if for some reason the development gets abandoned (although I had no such cases in my practice).