I'm pretty sure you can move between accounts under the same email address. Checking the battlenet site, it seems to cost RMB60.
I couldn't go all the way through the process, but I did the following before I had to stop as I don't have a second wow account on my email address.
1. Down the bottom of the battlenet page, choose 角色转移.
2. Select the character to transfer.
3. Select choose 转至其它账号, then 同一战网通行证中的魔兽账号 to move a character between WOW accounts on the same battlenet email address
I hope that helps, Klint.