EA Store, request a 10 dollar coupon from their customer support chat, voila, 39.99.
Don't trust any key sites, a distributor has been scamming large amounts of those sites by giving them fake keys and coming out with the cash. For any other game, sure, buy from a key site, but with APB, it's best to be safe and go with a reknown digital distrubtor (APB Site itself, EA Store, Steam, Xfire Store, etc)
