We Broadcasters can still get uncompressed audio from distributors, like the PlayMPE Service, and others. I believe the compression used by sources like Amazon and iTunes is available in "high res" like 256 or 320Kbps or better for a slightly higher price.
I don't know if they offer lossless compression like FLAC or not, tho, as I haven't looked for it.
Obviously, uncompressed is best, but at 256K MP3 the losses are so minimal, that a single compress/decompress to WAV cycle is so close to "never compressed" as to be insignificant. Keep it WAV after purchase, and you're good to go. :)
256K is also good to save space when ARCHIVING audio for posterity. :) (Or for off-site/online backup.)