An account-to-account character transfer is $25, but you can do as many as you want. It takes a few days to complete.

When/if you do make 2 new accounts, be sure to first go into Account Management on worldofwarcraft.com and send yourself an email from the Recruit-a-friend section of Account Management. When you use those codes to set up your new accounts, your main account will get 2 months free service.

Also, you dont have to go out and physically buy a new game, you can install the game on the other computers with your current CD's and "upgrade" the account online for the same price as buying the actual game ($15-20).