I have never dealt with them before.
http://www.newware.com/product_info.php?products_id=37801
I talked to them on Monday and they said they had 5 in stock.

Key code for a trial of StarCraft II: Wings of Liberty, good for 7 hours of online game time or 14 days from activation (whichever comes first.)

The code is entered here in the promo code box and the price changes from $15.00 to $0.00.