I paid about $8,000 to add the robotics to my HQ Fusion about 3 years ago. But that includes the tablet computer that the software runs on, along with Art & Stitch design software (though Prostitcher comes with a lot built in so you don't have to use A&S) It also required a different carriage.
Most of what you are paying for is a sophisticated CAD program, and they've never been cheap.