Spend what you can afford and upgrade later if you need to do so. If you are a beginner, don't put lots of money into a machine you may not use all that much. I have a lovely little Brother machine that came from Walmart years ago. It has made everything from prom dresses to curtains to quilts.
If you go to a dealer looking for a used machine, be sure you don't let them talk you into dozens of bells and whistles that you don't understand. Start simple. Quilting and sewing does not need to cost a fortune to be a great hobby.