That machine is actually not a long arm but is often called a mid arm and can be used off a frame or on. Its basically not that different from the babylock Jane or similar Juki or brother straight stitch. Lots of people bought this machine and used it on a frame but they do have limited space to offer you. I see them with frames go for about 1200 to max 1500 around here.
You can get a new straight stitch machine in the mid arm range my Jane was about 1000 on sale juki 2010q runs about the same and is a great machine and a new king size Grace frame for about 1000-1400 here in the US. I would look around some more.