Hey all, I've an opportunity to build a forum into a popular WordPress site. The forum will of course have a "premium paid membership" section for a few bucks you can get in on the "awesome" stuff. I plan also to collect user signups for email marketing products. It would not hurt for a CPA offer that would allow users to signup for free if they did a CPA or something. I'm looking for suggestions because I've looked at the "easy" WordPress forum solutions (bbpress for ex.) and I don't see how they would support paypal IPN. PHPbb is free but seems like mods to work it into WordPress and paypal are many but in beta or really old and unsupported. Anyone feel like saving me lots of time and research to share a winning combination for this purpose? Free is always best as I plan to role this out to several of my blogs that do well from comments.