umm isn't that exactly the opposite of what you always hear?
I've been 5 years and from what I gather there was some bartering >10 years ago (not sure the exact date, but my impression is it was in the 90s). However, it shifted to a "gifting" economy where you give out gifts with no expectation of return and any Burner who hears that characterized as bartering would be quick to correct you.
It's otherwise a gift economy. Reciprocation is fine, except that the initial gift shouldn't be given with the expectation of reciprocation. It's a subtle difference, but it works out OK. Some would probably object to the term "economy" as well -- you're supposed to have arrived with everything you need to survive, so all the exchanging is just for fun.