Software or VST Plug in to change song key

I get singers, occasionally, that want to record with Karaoke tracks.  I don't have any software that will change keys so they have to bring CD's with the tracks in the right key or in the case of one singer, he brought his laptop with his Karaoke software on it and we used that to generate the backup tracks in the right key (fed that to Sonar).
 
My question, is there a VST plug in for Sonar that will do this?  If not, what are recommendations for low $$ karaoke software that will do this.   I have a 15 day demo copy of PCDj Karaoke and it will do it, but its $100.  Surely there is something cheaper that can be used.
 
 

there is a free app on the net  called KEY CHANGER  http://download.cnet.com/...0-2139_4-10463799.html

I tried it and it works fairly well.  Just be careful on CNET.COM since they have lots of crapware links that you may not want.... search for the link to DL this.... or look on a different site.... I got this on one of my computers. I don't use it much because there are artifacts that I find objectionable. But it might work OK for what you need. 

I tried the Transpose (several of its options) and its not what I want.  I tried it on a single instrument track and on a mixed down track.