[skimoose]

I had the same problem the first time I tried. The items went into the cart, but when I attempted to checkout the site balked, then the items showed out of stock.

You need to be logged in, AND you must have already completed your account information. You need to go to manage my account and fill in your billing address, shipping address, and credit card information. It also helps to change your password to something you use instead of the one given by FIRST just to get into the site.

Then it might help to log out and log back in. When I did, I was able to place the items in my cart, and proceed correctly to check, where I then was able to select the billing address, shipping address, and payment method I previously saved.

Try that.