We have had entire local service weekends cost less than $200, slept 9 people in a single hotel room, and used hand me down tools etc.
So I hope people do ask us :)
The Worst Question to Ask About Charity - Dan Pallotta - HarvardBusiness.org:
"A 2008 Ellison Research study showed that 62% of Americans believe charities spend too much on overhead. In Paul C. Lightʼs 2008 NYU study, 70% of respondents said charities waste either 'a great deal,' or 'a fair amount of money.'"