I applaud your efforts. It is a great feeling to help others. I've done it for many years and have seen good results. I normally help 20-30 people with bikes each year.

In addition to working as a part-time bike mechanic, I work as a full time as a minister. As part of my ministry, I fix up bikes and sell them very cheaply (normally $5-10). Normally, the repairs far exceed the amount that I charge. Sometimes I give them away, but not to often. I've found that people respect them better if it cost them something. If its free, they don't take care of them. If you find this to be true, you may want to charge a minimal amount.

Thanks for hopefully being an encouragement to others.