Plan the workforce. If you intend to not hire a professional crew, you'll need lots of help. There are many jobs to be done. First there's the furniture moving, then wall preparation, floor covering, materials gathering and prep, cleaning, and don't forget everyone will have to eat. It can easily take a team of five people a full ten days to paint a two-story (approx 2000 sq.ft.) home. Get as many people to help as you can. If some can only come one or two days, great. Maybe others can fill in. Ensure you plan with your workforce members in mind. They'll need plenty of time to arrange days away from work. Identify a few key personnel:

In addition, paint features such as mold and mildew resistance are important cost factors. Many mold-inhibiting bathroom paints, for instance, cost substantially more than ordinary latex-acrylic paint—sometimes close to twice the cost. Also, paints that come with warranties from the manufacturer may be more expensive depending on the length of the warranty. (A two-year warranty is standard.)
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.