Not all Buffalo bands, but one of my favorite local labels just put up a bandcamp page. They've only put up a handful of releases, but there is a lot of good stuff, and there should be more to come. Everything is free / pay-what-you-want. Check it out.
http://feral-kid-records.bandcamp.com/
Music from: ANS, Ghaddar, In Disgust, The NoJons, Panaceja, Rational Animals, Sidetracked, Skate Korpse, Stupid Routines, Trystero, UV Rays, White York