Mixing multiple cans of the same color of paint into a larger container, such as a five-gallon bucket, will help ensure a uniform color is applied to your home's exterior. This step, called boxing the paint, is a method the pros follow. This step is important if, for example, you initially bought a gallon or two of paint less than you needed and then picked up the extra gallons at a later time.
The cost to paint a room will vary based on the size of the room, the type of paint you select, any ceiling or trim work needed, and any repairs needed. If no repairs or other additional work is needed, painting a room with contractor-grade paint could range from $1 to $2 per square foot, including materials. Selecting a luxury paint (some cost more than $100 per gallon) will certainly increase your house painting costs. Here are some additional examples of average house painting costs, per room: House Painting Arvada CO