If you are super new to sewing, then I would recommend you go to one of the quilt stores who have a longarm machine that you can rent by the hour. Before spending $20,000, even with $1,000 off, you need to find out if this is something you really want to do? All day? Every day? Or only for yourself? As a business? I've quilted for almost 40 years. In that I've figured out just what I like to do the most and I don't. I've thought long and hard about buying a longarm machine. It's not just the space. It takes quite awhile practing of a machine to get good at it. More importantly, what kind of servicing does the seller offer? Piecing a quilt is quite different than quilting on a longarm machine.
Good luck. And ask lots of questions. Look and try out several different machines.