Tell him you'll be an independent contractor. Advertise what kind of work you and I can do and tell Lee that he can hire us in specific situations. Now you don't work for free, you can satisfy your conscience, and you can not only work with me but stay away from large groups.

Volunteer groups tend to have a lot of money to begin with, mostly because there are a lot of people who don't want to do a thing but will make themselves feel better about it by donating money.