I purchased a year-end special deal, but it was the version 12 basic set, with some other freebies (piano and guitar how-to stuff). It was less than $100. The basic set comes with lots of different styles, and there is a user's group where members can post their own styles - these are free for download.
http://www.biabgroup.com/
I don't really use the melodist and soloist, at least not yet. I've only just begun. I played around with this a little, and while it sounds great as solo music, it interferes with karaoke where you really only want the background band.
I play piano/keyboard , so I also have a library of song books, most include the guitar chords, so it's easy to input them to BIAB. Try out a couple of different styles, set the tempo, and I'm done.
So far, I've done a couple of country songs - and an entire collection of Christmas songs. For Karaoke, it works very well with any song that would sound good as a piano sing along. It would be a little harder to add those unique instrument sounds that "make" a particular song (think of the opening and the drum solo from Wild Thing)
I will tell you that while the software comes with a large manual, I had a tough time getting started with the basics. Once I figured it out, I can now turn out a great song in about 10 minutes - 20 if I input the actual song melody. The instructional video might have been helpful.
BIAB lets you save your song as a midi file. Then I use Edirol to convert to a wav.
I'm having fun with it. Let me know if you try it and what you think!