I came across Karaoke_Version.com today and I am stoked at what these folks have to offer.
For $3.99, I purchased 2 versions of the backing track for Love Gun by Kiss. The 1st was a full version with drums, bass, guitars and vocals, the 2cnd was a modified version with only drums, bass and vocals. I can't say for sure as I haven't done it, but I assume I could make another version of the track and download it as well. The backing tracks are downloaded as mp3 files.
I found it to be a great product and a price that blows my mind. The song catalogue looks pretty good but I only browsed it briefly.
I personally find it great fun playing to a jam track. If you are curious and want a better idea of how it works I made a video of my experience from this morning.
This year the diet is definitely gonna stick!