My daughters have been involved in scouting for a decade, and I could say the same thing. Yes, over the years we've put a good bit of money into it, but all kids' activities cost something -- we never expected not to pay for things for them -- and scouting has provided a tremendous return on our time/money investment.
I run my troop with very minimal cost though. I have one girl who is economically disadvantaged - and I feel pretty strongly that Girl Scouts should be for all (Boy Scouts is different). Often, the kids who get the most value from Scouts are the ones whose parents can't afford much but Scouts - and Scouts is a stretch. I also have a set of twins - so for their parents, everything we do is twice the cost. We use cookie money for everything we can (and my girls don't sell a lot of cookies), have low dues, don't require sashes. If the girls want to go to summer camp, that's on their dime, we don't do that as a troop (but I have taken them to camp for a weekend as a troop). Total required spend for the year $12 in registration fees to Council (and I've checked the grant box on those more than once - we sell enough cookies that council can pay this girl's registration) + less than $30 in dues. When we do activities, I tell the girls the cost and that they can contribute to it or not as they (or their parents) see fit. If they don't, we do fewer activities. Most do. (And I kick in a bit, my troop is one of my charities - I buy them all sashes as a fly up gift, subsidized their weekend at camp, and don't bill back the troop for trips to the craft store).
There isn't a lot you have to do with Girl Scouts anyway (and Boy Scouts is different) that requires spending money.