I have been advised to pass on the following instructions to try to resolve the issue... Please restart Tor. If that doesn't fix the issue, please ensure that you're selecting a shipping option for the item you're attempting to order and clicking the 'Go' or 'Update cart' button, ensure that you're entering the correct PIN and also that you have enough BTC in your account to cover the cost of the order (inclusive of shipping). If that doesn't resolve the issue please ensure that you're using the latest update to the Tor Browser Bundle, and that you have installed it to a fresh folder (i.e. not over the existing installation.) Can you please let me know if this resolves the issue.