IGN gave the price in a lengthy hands-on with the four maps. Each is based on an area of the campaign, from start to finish. Hometown takes place in Texas, where the story began, but is ravaged by years of the apocalypse. Both Bookstore and Suburbs are set in Pittsburgh, where a large chunk of the story took place. Finally, The Bus Depot is set in Utah, near the end of the campaign, and even features giraffes in the background grazing as we saw in the story. Apparently they're very used to firefights taking place near them.
If you get the pack through the season pass, you'll also snag 60 head items for use in multiplayer. Naughty Dog hasn't announced what's in store for the other parts of the season pass, but we know it will feature some single-player content as well.