Borderlands has received two DLC packs so far but Gearbox isn't done just yet. According to studio boss Randy Pitchford, you might not have to pay for all of the new content.

"We are investing a lot of time in supporting the game with free updates and paid downloadable content. There will be some announcements on both fronts soon, I expect," Pitchford said in an interview with IGN. "We have a lot of motivation to do more with the game and have a lot of lessons we're applying not only to our immediate efforts, but to our ambitions for the future. I don't have anything specifics to announce at this time, though."

You might argue that the phrase "free updates" is simply referring to patches and doesn't entail additional content. Still, no one really makes a point of saying that a patch is free - they always are. Still, the freebies will probably be a lot less meaty than the premium offerings.