interior paint cost estimator
1 Interior paint itself costs anywhere from $12-$50 or more a gallon, depending on the quality. 2  Painting a 12x12-foot room, both walls and ceiling, can require $25-$100 worth of paint, plus $10-$50 for primer, brushes, rollers, drop clothes and other supplies. rate of no less than $1.80/sf including materials is realistic, acceptable and more than fair for a qualified professional to paint rooms with 9' ceilings. Expect to pay $1 extra per square foot for 9'- 15' and $2.50 extra for 15' +.