Hey Gaatgi, I have purchased some backing tracks from the link I mentioned at karaoke-version.com
Custom accompaniment tracks - play along music for guitar, drums, bass.... What I like is that I can customize any number of ways to make the backing tracks. Also, since I have a multitrack recorder, I have been able to download the individual tracks and mix them myself on my recorder.
One of my favorite methods of using backing tracks for learning a song is to have all the band (minus bass) on the left side, and the bass track alone on the right side. Then I can easily use the stereo balance on my machines/software to blend in how much bass I need to listen to as I learn the song. Starting out, I primarily concentrate on the bass track alone, with just a little of the band in the mix for context. When I am up to speed on the song, I prefer to play the bass line myself with the backing track on full left (without bass) so I am jamming with the rest of the band.
I have tried many other sources for backing tracks, but most of them don't measure up. I have tried to use Guitar Pro files, but even at my level, I know the bass lines are not very accurate on most GP files posted on the internet. Ditto with midi tracks I have downloaded from the internet. Of course, the best is still being able to listen to the original artist track, but sometimes I can't figure out what the bass is doing when the whole band is playing. Also, playing along with the original tracks sometimes make me feel I'm playing better than I really am because the original bass line is always there playing it correctly even if I am not.
I have become a big fan of Youtube.com, where I always search for Bass Lessons/Covers of songs I want to learn how to play. Quality varies depending on the video. But in the end, it still does not give you a backing track to play along with.
Well, $2.99 per song at Karaoke-Version.com is about the best I have been able to come up with to make bass backing tracks for songs I am serious about learning. And I have purchased a few titles to practice along with. Mostly songs that are more challenging for me to play. Otherwise, I still play along with original artist tracks because I already have them and/or can download them for free off the internet.
One final thought, is that the reason I am willing to pay for the Karaoke-Version.com backing tracks is because they also have the lead and backup vocals included with the song. In my band, I almost always sing backup, and some songs I actually sing lead. So I can also listen to and learn the vocal parts for the song. Bonus good deal in my case as I am not a strong singer and it gives me more chance to practice with the backing track. Some songs I play my bass by listening to the vocals, and not so much remembering the verse/chorus/bridge patterns in my head. Don't know if that makes sense, but being able to listen to the vocals and play that part correctly has saved me on stage when the vocalist, or guest vocalist, starts singing part of the song out of order (which happens). So I don't care much for backing tracks without vocals.