You can get this tabard for free and within minutes, even outside of the US*.
* Technically one of the terms you agree to is that you are a US citizen, but the same conditions apply to claiming any of the Trolli pet or tabard codes. It means they have the right to mark the code as null and void, but I personally don't see this being enforced.
1) Go to
https://www.pointsrewardsplus.com/ and sign up for an account.
2) Go to
https://www.pointsrewardsplus.com/coinquest-game and play 2 levels of the game; or wait 1 hour after signing up for the points rewards program and refer a friend.
3) Claim a tabard code from here:
https://www.pointsrewardsplus.com/rewards4) Redeem the code in your Battle.net client by clicking on your nickname in the top-right, clicking Redeem Code, and entering the code you claimed.
You can claim multiple tabard codes if you have enough points, so if you have a friend who can't access the website (it seems a little spotty), you can help them out!