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.
While many professionals use paint sprayers, they can leave drips and uneven coatings in the hands of an inexperienced user. If you’re set on DIY house painting but don’t have much practice, you may want to stick to rollers and brushes. Brushes are great for edges and smaller areas, while rollers can be used to paint large and long surfaces like siding and trim.
If you are painting for a client, skip the paint in the bucket, and use large trays. For faster completion and still quality results the 5 gallon bucket and strainer work great as well as a wood filler, 5-in-1 tool, screw gun (drill), metal joint compound tray, metal putty knife, wide drywall knife, mini hand-held paint containers (for brushes), and a mini-roller and corresponding nap (for edging, after cutting in with brush on the bottom, top and sides of wall, and the sides of ceilings, so that you don't see brush lines).
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.