I think I've spent at least $150 at DDV. All of the tracks are available at 320 kbps, and a few as uncompressed WAV files.
Unfortunately, the site is still kind of buggity, and the updated are infrequent, which keeps me from spreading the word outside of dedicated 313 circles. Still, I love being able to listen to this stuff without worrying about wearing my records out. I've spent a fair bit at bleep.com too. Always avoided i-tunes, because of the relatively low quality, and less than amazing royalty rates (from what I've gleaned). I'd rather support the little stores anyway. I think techno *needs* digital distribution now. There is a big audience out there that doesn't go to clubs and isn't even aware that vinyl still exists, but they love the music when they hear it. While they'll never be hardcore techno soldiers or join the 313 list, they're a valuable source of revenue and word-of-mouth. - bp
