Before opening link simply disable javascript in your browser settings (you can also use a browser extension like noscript) and you should be able to checkout without a problem (will need to use a US/Canadian address for billing address though (Google)).
If you are wondering if its worth it since BF4 comes out in 4 months, yes it is, especially base BF3 for only $5, also premium will allow you to play the BF4 Beta when it opens sometime at the end of September.
BF3 Base Edition [$5] http://store.origin.com/store/ea/buy/productID.225064100
BF3 Close quarters is free this week (Included in premium editions) simply redeem code[BF3E3] through Origin.
BF3 Premium Edition [$19.99] (Includes Base and all 4 DLC Packs) http://store.origin.com/store/ea/en_US/pd/productID.25575120…
Premium addon[$15] (For those who already own BF3)
http://store.origin.com/store/ea/en_US/DisplayProductDetails…
Just got the premium pack for $20, thanks OP