Plan the budget. Costs will vary greatly, depending on price and quality. Choosing mid to upper-grade paint, expect to pay in the area of $350.00 in paint alone for a 2000 sq. ft. house. Add another $100 to $200 in brushes, rollers, pans, tape, and other materials. Don't forget food, if you plan to feed your workforce. When it comes to materials, not all paints are equal. Some truly cover with one coat, some say they do but don't. Your costs will double if you have to apply two coats to everything, so buying the cheaper paint might cost more in the long run. Trust your paint professional salesman (to a certain degree) to tell you which paint to buy. You can generally go cheap on primer, expensive on top coats.
Prep the house. Wash the walls, remove wallpaper, patch, spackle, seal stains, dry and sand before you attempt to paint. Now is also the time to apply painters tape for trimming, lay drop cloths, etc. Remove all outlet and light switch face plates, collecting screws in a zip-top bag (good opportunity to wash the face plates all at once as well). You can also buy your paint at this time. Don't wait until the last minute. It can take hours to mix many gallons of all your colors. Remember that traffic triples at your home-supply and hardware stores on weekends. Buy on a weekday if possible.
A more user-friendly option is a water-based “latex” paint, which blends acrylic pigments with a thin base for easy application with a brush or paint sprayer. Although many water-based interior paints are promoted as one-coat wonders, there can still be a need for an initial primer coat followed by one or two coats of latex paint. Water-based paints are very low in VOCs, which means minimal odors during the drying period. Most spills can be wiped away without the need for chemical cleaners, and clothing containing latex paint can be laundered in water and detergent. Water-based paint is a good choice for first-time DIYers and their younger assistants.
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.