RM 1.1 Using RM with paid content

Our gaming community has been debating relaunching our site with a new theme, as well as the Resource Manager. We have plans to use the RM to allow users to purchase in-game content (virtual and downloadable) via the RM, but we're a little lost on how to utilize the RM for such a thing.

I'm aware of the external purchase and download function, as I've seen it on a number of other communities. What I'm seeking here is, some tips on what to use as a payment module. Is it possible to link to a PayPal donation / transaction page, and will the RM be able to confirm the payment was sent before allowing the user to "download" the product? Or, do I need to use some sort of third-party e-commerce software such as ZenCart?

Thank you!
Perhaps I'm a bit confused, but I'm not sure how this would help?

I'm hoping to allow users to purchase directly from my site, only being redirected long enough to make the payment via PayPal, and automatically redirected back and allowing them to download an item once the payment was confirmed. Similar to what Nexus does for Invision Power Board, if you're familiar with it.