Prepping a house costs anywhere from $0.50 to $2.50 per square foot. This is almost always included in the total project price. However, the DIYer might negotiate some discounts for completing this work on their own. Be warned, proper prep is key to the quality and durability of the finish. If you do this work yourself, the contractor might no guarantee to finished product.
Another type of paint is on the market that claims to be a primer and paint in one. Basically, it’s just thicker paint and costs twice as much as regular paint. Most professional painters aren’t fans, but if you have exterior walls in excellent condition already, and the self-priming paint is the same color as the original paint color, it could certainly save painting time with one coat going on instead of two. House Painting Denver Colorado