Ok I have that machine. Retail on it is usually $899 US, although you can find it on sale for $599. If someone paid $2000 for it, they might have purchased it as part of a quilting setup, with a frame. I bought mine from a quilter who had it on a New Joy frame and upgraded to a larger setup. I paid $400 for the machine and frame, gently used. I don't use it to quilt anymore because I acquired an 18" stretched Singer. It's now my "daily driver", my piecing machine.
The Brother 1500 is an awesome machine, easy to operate, reliable, solid. As I said, if it were me, and I had the opportunity to check the machine and make sure it runs, I'd buy it in a heartbeat. Yes, even though I already own one. I'd buy a second one as a backup!