I can only buy 1? I don't have 1 in my cart...
Just in case anyone else runs into this:
I clicked to add Tempest to my cart and realized I had not logged in yet, so I choose to log in before looking in my cart. After login, my cart had zero items, so I added Tempest...but I received the "You canonly have 1 of these blah, blah, blah...." message. I logged out, cleared my cache and tried again--same result.
I logged in from another PC...same result. There was nothing in my cart, but I couldn't add Tempest.
Solution (at least for me):
Log out. Choose Tempest, and then view cart--I was prompted to log in, which I did. There, now in my cart was 2 Tempest. I edited the cart and checked out. Knowing this now, I probably could have added anything to my cart and removed it later.
I post this here just in case someone else has the same problem someday.....