Copying wow into another folder has nothing to do with being able to play multiple accounts. If you buy new boxed versions (I just bought 3 WoW battlechests from Walmart), and log into your trial account online and go into account management, there is a place ot enter your retail keys that come in those boxes and upgrade to full paying versions. If you have 10 day trial time left, you will still be able to play those for free before your 1 month of free time that comes with the game starts. After that 1 month is up you will then have to enter credit card info for account or use multiple game cards.\\

Hope that helps.