There is an organization in my town that takes donations of old bikes, fixes them up, and sells them to homeless people/poor people for a nominal amount (like, $10). They also do repairs. I believe it's all volunteer run, and the space is provided by a cool non-profit organization that takes donations of old cars (you get a tax deduction for this), fixes them up and makes them available at low or no cost to low income people. Two good organizations. I'm quite sure that the bike shop is a labor of love, there's no way that they could even be breaking even.

For better or for worse, I doubt I have been mistaken for homeless while commuting on my bike. I never ride wearing "civilian" clothes, and I think I look "geared up" enough that even my enormous backpack probably doesn't make me look homeless. I do sometimes wish that I blended in a little better and didn't look like such a bike alien, for instance if I ride to the grocery store.