I have not played or logged onto my World of Warcraft/Battle.net account in several months. I am now on the World of Warcraft website and I clicked "manage account". I am trying to log into my Battle.net account. I type in my e-mail address then my password and click login. A message then comes up that reads -

Battle.net-Account
"Please activate the Battle.net Authenticator product attached to this account, and enter the six-digit digital code that it generates."

Then it gives me a space to type in some sort of code. I don't know what it wants me to type in? And does getting this code cost money Please help!

This is what the screen looks like -
http://i31.tinypic.com/8vpudu.jpg