It's at least 11, as it was buying price for many bots for about a month very recently, as I mentioned already in my recent "invalid" price suggestion.

Now it dropped, but slowly growing back to (presumably) the same 11 keys value and already is at about 10.

12 is the lowest I can go eventually for a real human being, by looking at these bots, but I hope to find someone to buy it for 13, and believe 13-14 to be the fair price.

Fun fact: I got mine for 16 keys when keys were much cheaper like forever ago (2014-2015?)