I have a VERY small machine and can just about manage to FMQ (Just beginning so stippling only so far)/SITD a twin. I just quilted made a queen/king? 88"x88" in 2 halves then joined them quilt layer only right sides together quilt side. Turned over, trimmed excess batting and backing to overlap and hand stitched the seam down the middle. You can not even notice on the top. I agree the cost of quilting has surprised me, it is not just that jelly roll or couple of charm packs, the extras all add up. But I hope you can find like others suggested cheap sources, I think using sheets as backing a great idea, though imagine you should prewash first to check shrinkage/colour. Also I decided to make smaller projects, table runners and cushions add a great touch, and after all you only have so many beds in the house! ( I plan to upload pic of my large quilt later, I will add a pic of my machine- I bet my machine is much smaller than yours- I am in Japan-everything is smaller here!