Keep in mind you must initiate borrowing from a Kindle, not a computer browser, or it will turn into a purchase instead. Yet you must return it with a computer browser (manage your kindle page), not the Kindle. A bit inconvenient sometimes. Also you cannot use Kindle apps to read them, only a Kindle device.
For some reason right now I'm able to borrow a second KOLL book even though I have one checked out. Interesting. Looks like it might be because the one I borrowed was removed from KOLL list after I borrowed it. So maybe I sort of own it now. Good thing, it is taking me forever to read it!
I created a 'KOLL' wish list to keep track of books I might want to borrow in the future. Browsing the KOLL list directly is not very efficient (too much 'junk' to sift through) so I just add them to my KOLL wish list as I come across things that interest me.