Depends on where you're at, do you already have the 10hrs of complex and all the cross counties done? Can you perform precision landings, chancellery etc?
For me the initial CFI was the cheapest thing I've done (minus my GI), it was well under 2k, really as all self study and tutoring folks.
The CPL is just a overblown PPL, if your logbook is to CPL specs there isn't really much to do.
I'd imagine the speed of which to complete all of this is more on you than the CFI or program, and part of becoming a CFI is learning how to teach, yourself included, I spent next to no time getting instruction for my CFI.
I'd wager you could get it done for less if you're already to spec and can study and read a PTS yourself.