Not sure if its posted or not, but I found this deal on Sunday, and its still active.
You can buy it online at Best Buy, but at target, you have to go to a B&M store (Physical Store).
I'm not sure about buying Original World of Warcraft and getting a free TBC at the local Best Buys, but it doesn't hurt trying. (Call first)
Free Burning Crusade with World of Warcraft Offer
Original WoW for 19.99 PLUS The Burning Crusade for free.