It would appear that wpplugins has a new pricing model. AIOSEOP costs $39 (special price; normally $69) to download, plus $3 per month for support and upgrades. That's more reasonable than some of the numbers being speculated, and $3/month is pretty reasonable for support, but I still don't agree with a monthly subscription for plugin updates.

It also seems that over the weekend the free version of AIOSEOP hosted on wordpress.org/extend finally got updated for feature/bugfix parity with the pro version. Prior to that, the version from December 2009 was still in the repository (including a critical, unfixed security vulnerability). If it hadn't been updated, I would have started to question the conformance of the free version to the unwritten guidelines for free "upsell" plugins in the repository.