That thread that Tim posted is where it's at. Most folks don't wanna trade but would rather you do something in order to receive the playbooks. I've personally spent more than a few hours making art for Johnstone and Ben to get some of the groovy playbooks they've written or others than I didn't have access to, I've donated to charity, come up with custom moves, &c.
As for me, I've been known to part with playbooks for engaging with various threads or subforums that I think need more attention. At this point, the only thing I'm looking for is custom content, community involvement or solving design problems.