It's a simple $15/month per account, though there are optional services:
- Each expansion that comes out every 1-2 years is $40, not bad really
- 50 character limit per account, 10 character limit per realm per account, 1 heroic character (death knight) per realm per account
- Character realm transfers are $25 per character if you want to transfer realms, has a 30 day wait after that
- Character rename is $10 per character, 30 day delay until you can do it again to same character
- Character recustomization (gender, skin color, etc) is $15 per character, 30 day wait after usage, optional name change is bundled. Though, the game features a barbershop where you can change your head hair, facial hair, tusks, horns, tatoos, earrings, etc for free. Well... free as in it doesn't cost real life money. You do need gold that you collect in the game to purchase barber shop stuff though.
And VT, aren't we already friends? *tight hug*
BTW, difference between barbershop and paid customization is barbershop does cosmetics whereas paid customization does skin color, gender, and name, as well as barbershop services of course.