When you purchase Borderlands 2 next month on the 21st of September, you may as well buy yourself the newly announced season pass. 2k Games have said that four expansions (DLC) for the second game are going to be released. Not sure on the price but I would guess to be around 800 Microsoft points to 1200 points. The season pass that you pay upfront for will guarantee you a free download of each and every new content, all four I should say.
The season pass also was introduced to the Call of Duty franchise and a lot of players have bought it. All the new Call of Duty DLC would arrive early to players and other players who don’t have the season pass would have to wait a few days in order to purchase. I believe that Battlefield 3 has something similar, I think it’s called a Premium Member. I’m not sure how much the Borderlands 2 Season Pass will be, but it’ll be cheaper in the long run to buy the Season Pass than buying the downloadable contents separately.