With the real-money auction house, Diablo III
players will be able to buy and sell the loot they find in the game using actual currency from approved third-party payment services or using their Battle.net Balance. Players will only have access to the real-money auction house while playing in their home region. That means that, for characters created outside of your home region, items cannot be bought or sold in any real-money auction house.
To access the real-money auction house, click on the "Auction House" button on the left-hand side of character campaign screen and then on the button in the upper right-hand corner of the auction house interface. This will switch you between the gold- and real-money auction house. Visit this page
for more details.