I am a long-time hand quilter and a recent Long Arm Quilter. I love 108" backing fabrics but they can get expensive. I also use cotton sheets for backing all the time and have no problem with either. However, do pay attention to thread count. WalMart has a 200 threadcount that is wonderful!...soft and inexpensive. I recommend it! Also, what is the problem with your quilting showing up on a solid background. I want my quilting to show up!....so blacks and navy blues are my favorites! So glad to see this thread and remove the stigma of using sheets for backing.