Similar to the Pay Per Post option included with WishList Member, there is a Pay Per Course option included in WishList Add-ons.
The video walks through the Pay Per Course settings and available options.
Note: The WishList Member Courses Add-on is included in the WishList Member Add-ons plugin. More details on WishList Member Add-ons can be found here.
Additional WishList Member Add-ons articles/videos can be found here.