Second: all the tricks of the trade in regard to "cheating" customers is for hustlers and cheaters and NOT established businesses. At the end of the project the job should come out looking professionally painted as specified in the contract. A selected color that takes multiple coats that was not calculated by the contractor should cost more money. It's not the fault of the painter.
Paint gets more expensive as you go from flat to gloss. The difference is usually around $1 per gallon per sheen upgrade. Flat is the cheapest, then matte flat or eggshell, satin, semigloss then gloss. Paint also gets much more expensive the darker it gets. A white or neutral paint color can be as much as $20 less expensive than a deep base red or blue.
The graph says the average cost to paint a home interior is $1600; at the high end, $4,000. But for what size home? I'm getting estimates for painting an 1800 square foot townhome in the range of about $6500 - which includes sanding and repainting all doors, and painting all trim, walls and ceilings. What does the range above include and for how big of a home? Thanks.

Home Interior Painter