Battlechest comes with the 1 free month still for the Basic WoW Install/key Skuggo ;p Create Invite-a-Friend acct, then upgrade with bchest CDkey and you have 40 free days on that account, then after those're up your main acct gets a free month too, and you can install BC immediately after the wow CDkey if you want. Most free-time you can get :p

I'm not fond of online purchases, especially something like a CDkey, so use that at your own risk.