From Diablo Wiki
no edit summary
The Battle.net Balance, AKA [[Bobby Bucks]], was revealed in December 2011
.[http://diablo.incgamers.com/blog/comments/battlenet-balance-named-live-soon] This is Blizzard's term for the real currency balance tied to your Battle.net account. This money is used for purchasing items via the Diablo III [[Real Money Auction House]], and can also be spent on other products from the Blizzard Store, including games, [[merchandise]], and [[World of Warcraft]] fees.
The introduction of real money currency trading in Diablo III was a very contentious issue. While this article covers only the Battle.net Balance, you can find full details about the controversy in the [[Real Money Trading]] article.