Hi David -
I think you probably have the gist of it ... I don't think there's any significant distinction between purchase and acquire that is relevant to the exam, but I would imagine that "acquire" is just a catch-all for any situation in which you don't own the resource as a result of paying for it. For example, I might acquire a resource as part of a barter agreement (e.g. if you design my website for me I'll allow you to advertise your business on it for free), or might rent or borrow a resource without actually buying it.
I would imagine this could also have been written as "purchase or otherwise acquire" since purchasing something is one way to acquire it, but you can acquire something without necessarily purchasing it.