I transferred around 35 toons to Kil'Jaeden a while back. I had to do a server move and faction change. I got lucky and found a guy at blizzard that gave me free faction change for each server move. However, he is no longer there and the girl who replaced him refuses to give any kind of discount. I was going to move my DKs and Mages over but now that would cost me close to $500 to move them.

I didn't have any problems with credit card errors. I had two battle.net accounts and he even let me move two tanks to a new account on another battle.net account. That guy was awesome.