Four pieces of campaign DLC will add to your Borderlands 2 experience after the game's release on September 18.
Gearbox revealed their committment to releasing the extra content at their PAX Prime panel today. CEO Randy Pitchford noted to me that they'll be on par with the scope of something like Borderlands 1's General Knoxx DLC. Each one will run you $10. No other details were revealed, though Pitchford stated that the four DLCs will be self-contained experiences for either players looking to continue leveling after completing the main game, or to experiment with new alternate characters.
Fans can get all four DLCs with the $30 Season Pass. Gearbox also announced that they would have more details by the release of the Mechromancer DLC, which arrives October 16.