How are you planning to sell your quilts? You should be realistic about how much you can sell them for at craft fairs, etc. because when you factor in the cost of materials and for your time and labor, plus the cost of renting booth space at craft fairs, for example, then selling your output, especially when you're first learning, may not be what you're hoping.
Oh, and--in my experience, even a twin-size quilt is pretty big to quilt on a home sewing machine (any mine is a Juki with a larger-than-usual throat space).