I was in the same boat you are in last year, and I too went to the big quilt show in Chicago and tried all the long arms (I had previously tried a few of the sit down machines and liked those too).
I decided on a long arm as opposed to a sit down for one reason ... I HATE to baste quilt sandwiches!!
The long arm I fell in love with (Innova with lightning stitch) is pricey. Like you, I do not want to go into a long arm business, I just want to quilt my own quilts. As a neophyte to long arms, I could not justify spending that much on a machine without knowing that I would like it, use it, and become good at it.
So I scoured all of the various internet sites for used machines for sale that were local to me (within a 200-300 mile radius). I began my search in June, and found a machine and frame at a great price in October only 50 miles from me. I found my machine on Craig's List.
So ... if you think a good used machine is the route you want to go, just be patient and keep checkin all of the internet sites!!