What's the best plugin for paid subscriptions to PDFs?

I’m looking for the best plugin for this functionality: A PDF newsletter will be published weekly and needs to be available to purchase and download from a WordPress website. We need to be able to sell these PDFs in a few different ways:

• One-at-a-time
• On a yearly subscription basis
• On a seasonal subscription basis

Is there something out there like this? It would be nice if there was a way to attach the downloads to a user profile, so that if somebody logged in they could view the archives they had already paid for without having to re-purchase the PDFs.

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On another note, I need a plugin that automatically publishes new blog posts to a Facebook Page (that is; not a profile – a company Page). I’ve tried a few different things but they get into API keys and whatnot, which is giving me a headache. What’s the easiest way to do this?

Thank you in advance!