We will build you a treehouse

So some friends and I are looking for a place where 7 people can stay for a few days relatively inexpensively, or free. It doesn't need to be extra fancy, just somewhere we can all be in the same place and cook a few meals. You're house (without you in it) would be perfect. But we'd want to thank you for letting us stay there. And we'd want to do something beyond money or cleaning it or whatever. No, I think we'd like to build you a treehouse. How this works is you go on vacation, we stay in your place and build you a treehouse. You get a treehouse for free and we get a place where the 7 of us can hang out together and catch-up.

The idea is to take this on a larger scale and connect people who are looking for a cheap place to stay with people who need cheap labor. It could be anything. Farming, planting, trench digging, etc. The people doing the work probably wouldn't want to work 15 hours days, but they would have to be willing to do the project right. This could totally work with the right people organizing it. I mean, say you're going to be gone for a week and that old shed in your backyard needs to be torn down. Just let some pre-qualified, insured people stay in your house and tear it down for you (the shed, not your house. You'll need to leave specific instructions). Maybe you even collect a very small amount of money for the utilities.