(@mikeschinkel: Before edit title was: is there a plugin/set of plugins for providing subscription to digital assets on an individual or large scale?)
I'm trying to set up a site where a substantial amount of PDFs will be sold both individually and a subscription will be sold to a library - so anyone from that library can visit the site without a paywall (so, based on IP). does anything exist for wordpress like this? bonus points if its free/open-source and not paid...