In the interest of going above and beyond the call of duty, I'm posting two distinct bands that have found success outside of mainstream record labels.
First, I have a clip from Pig Destroyer. They are signed to Relapse Records, which started by representing three bands, grew into wholesale and distribution, and has expanded into a well-respected extreme music (e.g., more abrasive sub-genres of punk rock and heavy metal) label. Pig Destroyer is not a band that's ever going to find themselves on a mainstream radio station, if any radio station. I have seen their videos on television, but only on programs that specialize in similar music, which are on specialty channels and at obscure hours. Their music has sparse appeal, so the DIY method could only take them so far; without support and the internet, I would never have heard of them. They produced this video for an unknown amount of money (If anyone can find the number, I'd be most grateful), and it's received more than 500,000 views.
The other band I'd like to share with you is called Vertigo Venus, and their situation is very different. Their sound is much tamer, and as a result, has wider appeal than Pig Destroyer. They, however, are unsigned. Having recently played South by Southwest in Texas and signed a contract to put their music in television programs, though, they're doing a fair job of it without a label. They do shows in and around Albuquerque (including an upcoming performance at NMT on 4/29), and distribute CDs through a local wholesale owned by a friend of theirs. They're looking for support through specialty punk and electronic labels (e.g. Epitaph Records and Metropolis Records). This video was made in the basement of an old strip club for eight pizzas. It has received over 14,000 views, but comparing the two videos belies the kind of resources available to the respective bands.