I'm assuming that if you can go to the paypal order site and still add one to your cart and pay, they are still available. When they sell out, I assume that you will no longer be able to pay for one, and the paypal pay site will not work for anymore orders. (I could be wrong about that, so don't hold me to my words).
The last update was that there are 10 left, and I think that was from two nights ago (scroll up this page to see Spark's post on how many were left at the time of that post). I would just order one right away without any hesitation if I were you.