IMHO, the best thing to do is pay the 15% Paypal fee, so you can actually do stuff with the money earned right now (if you do not plan to buy items or any of the Blizzard services below anyways..).
From the official Battle.net Balance FAQ:
With Battle.net Balance, you can purchase:
World of Warcraft Character Services
- Appearance Change
- Faction Change
- Name Change
- Race Change
- Realm Transfer
World of Warcraft Guild Services
- Guild Faction Change
- Guild Name Change
- Guild Realm Transfer
- Guild Faction Change + Guild Name Change
- Guild Realm Transfer + Guild Faction Change + Guild Name Change
- Guild Realm Transfer + Guild Name Change
World of Warcraft Digital Upgrades
- WoW: Battle Chest to Wrath of the Lich King
- WoW: Battle Chest to Cataclysm
- Wrath of the Lich King to Cataclysm
Other Digital Blizzard Games
- Diablo II
- Diablo II: Lord of Destruction
- StarCraft II
- StarCraft Anthology
- Warcraft III: Reign of Chaos
- Warcraft III: The Frozen Throne
Note: Battle.net Balance may only be used on digital versions of the above games at this time. Battle.net Balance cannot be used to
purchase physical copies of these games through the Blizzard Store.
Additionally, World of Warcraft Character and Guild Services are
currently unavailable for purchase using AUD.