Saw this under the account comparisons between VIP/Premium/Free Player ... can one still buy these packs? or were they only available during pre-ordering of the expansions?
You can still purchase the pack. Go to https://myaccount.turbine.com/ and login with your username and password. Then click the gold and blue "Upgrade Now" button (if that is still how it is configured-- been some time). Select the the option you want (the Adv Pack) and agree to the payment plan. Agree to the Terms and Conditions on the next page and submit. The system will add the keys to the account for you, and all you need to do is fully restart your game and log in.