Clever people are abound. As I mentioned in a previous post, I recently went camping at a campground in New Hampshire.
This campground had a lot of people who stayed all season in RVs, in addition to folks who were there for just a few days (mostly tenting) like I did. On Sunday, when most folks were packing up to go home, some guys were going around in their pick-up truck to all of the tent sites from the non-seasonal campers. They were collecting the unused, leftover firewood that was purchased at the on-site camp store. That's a big savings. And so smart. They told me they also bring firewood from home, which is much cheaper than buying it at the camp ground. (Be cautioned before you attempt to bring firewood from home. Many campgrounds do not allow this. One reason of the prohibition is because you can easily and unintentionally bring invasive pests and diseases to the campground which can destroy trees.)
I practiced a little of the firewood frugality as well. We gathered some wood from the nearby forest within the campground, though we purchased most of our wood. Before the guys came around, I had returned an unopened package of firewood a neighboring camper had left behind. Cha-ching. I made an quick six bucks.