Painting is one of the quickest and easiest ways to give your home's interior a facelift with dramatic results. Fortunately, it doesn't have to be that difficult. Home improvement stores offer samples that you can take home. With these samples, you can try a few colors in large swaths on your wall to see the how the paint interacts with the room's natural light. Compare it against design elements like pillows or furniture to see whether it will work with your overall décor.
Take for example, I charge 1.75 sq foot for 10x10 room with 8 foot ceilings. By my calculations this would cost $175 with floor space sq foot, but with you method, it would cost $576.00 That is outrageous. Of course I didn't subtract the windows and doors, which is another thing that makes no sense. Cutting in around those windows takes more time, then just rolling a wall.