I purchased 5 off blizzard store yesterday (you have to do it via your battle.net account). There is however a maxium of 5 that is in place at the blizzard store. I emailed them to ask if I can get more (via multi transaction) but have yet gotten an answer. If you need 10 new accounts, I would make sure you can get tall 10 at once...or you will have to ask someone else to help you buy the other half or be stuck buying 5 more sets at full price.