For those who still have a free night available, if you wait until October 1st, it will be converted into 2 BOGOfree.
So if you use it now, you can get around 150$ value, if you wait, you could get much more (if you were planning to spend 4 nights somewhere ofc): it's very surprising but the free night will be applied on the most expensive of the two nights! Let's see if there is some limit to it...