Exterior paint averages $25-$40 a gallon, and a 3,000-square-foot home takes 15 or more gallons of paint, or $375-$600 just for the paint. However, really premium paint can cost $50-$100 a gallon, or $750-$1,500 for that large home. Doing it yourself also requires renting a pressure washer or sprayer for $50-$100 a day; extra-long ladders or scaffolding at $20-$75 daily; and a power sprayer for $50-$100 daily, plus masking tape, drop cloths and other supplies. However, it's possible to paint a large, two-story house for materials-only costs of $400-$600.

On average, expect to pay $0.60–$1.60 per square foot for exterior painting. The average for painting labor across the country is $30–$40 per hour before you pay for paint, painting supplies, location costs, and equipment. To get a very general estimate, though, painting contractors will take into account the square footage of your home and the number of stories and also factor in normal prep work.
Before hiring a painter, you should get a detailed estimate from them. This should include costs for labor, materials, paint, and the timeframe of the project. Covering details upfront will prevent issues from emerging later on. Ask the painter if they charge for travel time, whether their estimate includes pressure washing and caulking, and any other questions you might have.
The following guidelines will set you up for success. First, start at the top and work down. Second, paint out of the sun’s glare, since the sun will cause the paint to dry too quickly and flake or blister. To avoid marks, try to brush from one wet surface onto another. If you do have to paint onto a dry surface, overlap the wet paint onto the dry surface by several inches.
After you’ve bought your materials, prepare by removing all the furniture from the room. Next you can wash the walls and fill in any holes with spackle. Make sure to lay drop cloths or old sheets on the ground to protect the floor from paint. When you’re ready to paint, start with a layer of primer to cover all the walls. Once that has dried, you can paint with color. Use small brushes to paint edges and large rollers to cover the rest. For tips on choosing the perfect colors for your home, read on!
However, some water-based paints are easier to work with than others. The first coat of paint may not provide complete wall coverage, or the color may not be quite as saturated. Some of these problems can be addressed with a separate primer coat, but this is a time-consuming project. The ideal solution is using a higher-quality paint that combines a primer and a finish paint in a “one coat” product.

Most of a projects price is the cost of labor at $25 to $75 per hour. However, most contractors bid out based on the entire project which includes all work hours. Hourly rates are only useful if your pro asks to do the job as “time and materials.” However, be wary of this pricing structure, it usually shows the contractor is uncertain how long the project will take.