We'd already noticed last week that the Authenticators in the US store had gone free shipping, but now official updates on Blizzard's site say it's true in the EU as well. American authenticators still cost $6.50, but you no longer have to pay anything extra for shipping, and EU authenticators have had their price dropped to €6.99. That's still over $10, but they're at least cheaper than they used to be. There's a drawback, however: apparently they went with cheaper shipping, because you can no longer track shipments of authenticators, and shipping will take a little longer (up to 15 business days in the US). Which makes sense, given that you want these things as cheap as possible.
Ancilorn answers some other Authenticator questions as well -- there's no discount for buying multiple units at all; what you see is what you get. And while the only authenticator for purchase at the moment is the Corehound branded unit, there may be more art available in the future, and of course you don't need a Corehound-branded Authenticator to get the Corehound Pup pet. Any Authenticator will do that, including any of the authenticators made for mobile phones, as long as it stays attached to your account. Whew -- that should answer all the questions anyone has. As we said the other day, if you don't have one of these yet, it's probably time to look in to getting one. Not only will your account be more secure, but you'll get that free pet as well.