You can free-motion quilt on any machine as long as you can drop or cover the feed dogs. And you can do straight line quilting, such as grids and in the ditch, with almost any machine with a walking foot. You can combine machine and hand quilting in the same quilt. That is, do the straight-line quilting on the machine and then hand-quilt the curvilinear designs. So there are options that require little to no expense for you while you explore machine quilting. When you start wanting more harp space, there are many domestic machines with 9" harps. The least expensive are straight-stitch only machines like the Juki 98 or 2010, Brother 1500, BabyLock Jane, Janome 1600, Elna 7200. I've seen those for as little as $600 new. Full-featured domestic machines with 9"+ harps include the Janome 6600/ Elna 7300, BabyLock Quest Plus (I have one and LOVE it-it's been replaced by the Serenade, so the last ones are being discounted), Pfaff Smarter C1100 Pro, Pfaff Expressions line (10" harps-3 models), Janome Horizon/Elna 740 eXcellence, and Bernina 820. My best advice to you is to start machine quilting with what you have, while starting to research these models. As you determine your needs, that will guide you. When you are ready to buy, TEST-DRIVE machines on your fabrics, yours pre-made quilt sandwich samples, with your favorite threads. Also haggle, having shopped around and read reviews on PatternReview.com which usually include price. Even post on PR and here about your "finalists". I know this is a lot of info, but I recently made dramatic upgrades to my sewing machine, batting and thread choices, and sewing room. I now have several machines I love, but my favorites are my featherweights (of course), Bernina 930 (found it here on QB-from the most lovely quilter!), Quest Plus, Bernina 440, and Bernina 820. All used except the Quest Plus, which is an affordable DREAM, and the 820 (which I only have due to 48 mos interest-free financing).