1 Labor for painting a 12x12 room will cost $150-$450. 2  Total cost to paint a 12x12 room is about $250-$600. 3  Total cost for painting all the rooms in a 2,000 square foot home will be $1500-$3500.4  This cost could skyrocket if expensive materials and high-cost labor are used. Labor costs $20-$45/hour. 2  Painting a 12x12 room will require 1-2 gallons of paint ($40-$100). 3  Labor for painting a 12x12 room will cost $150-$450. 4  Total cost to paint a 12x12 room is about $250-$600.