I'm not sure how the frames you are looking at are priced. You might want to consider making your own tabletop quilting frame. This website offers a kit, and Kenneth Lund has a lot of Youtube videos that show how to put it together and how to use it. There are also several threads on the QB with photos of people who have made modifications to this frame. You might want to check it out:
http://machine-quilt-frames.blogspot.com/