All three choices sound attractive to me. If it is a new to me author or still fairly new to me author, I would rather read it in my Amazon Prime Kindle Lending Library. All books in the Amazon Prime Kindle Lending Library are also Kindle Unlimited titles, so I guess I am saying Kindle Unlimited if I was a subscriber. I do so many books for review that the books I pay for and my monthly books I borrow from Amazon get pushed back last every month to read my reviewer copy titles first, so Kindle Unlimited is not advantageous for me. I do still have an awful click crazy purchase habit for authors I love or new to me authors reccomended by others when their books are .99 to $4.99. So yeah I would say that is the magic price range to build up new readership.
Would you rather:
1- Read a book on unlimited for free.
2- Pay for a 2.99-4.99 book
3- buy a .99 book