Specify whether the contractor or you will supply the paint. Check Consumer Reports' paint ratings: In its tests, some relatively inexpensive paints performed better than more expensive paints and cost $10 to $20 less per gallon. But keep in mind that most paints will resist cracking, peeling, mold and mildew. Who does the painting — and how well they do it — is more important than what's in the bucket.
As a former professional painter, something that drives me crazy is when I see painters cut in around wall plates. First of all, the amount of time that it takes to cut in is usually much longer than the amount of time that it takes to simply remove the wall plate. Secondly it does not look nearly as clean as it does when the wall plate is removed and thirdly it can invariably leave paint on the wall plate itself which also looks sloppy. Make sure the painter takes them off and then reinstalls them. It's less time.
Deciding which paint to use has gotten much easier now that acrylic latexes have pushed oil-based paints almost to extinction. The acrylics offer superior performance (they don't harden with age, the way oils do, so they move and breathe without blistering), they don't mildew as readily, and they emit fewer VOCs, so they comply with new air-quality regulations. They also work over both oil- and water-based primers.
I am in northern Nevada and you have not yet gotten sufficient responses to provide a painting cost chart showing the averages. I do have a quote from an outside (Not Homeadvisor referral) painter who is local for $2,750 for soffits, patio cover and posts, Garage facia (redwood clapboard above (~300 ? Sq. Ft.) on a 2046 Sq. Ft. home where the walls are 9 ft tall and it is fully stuccoed with plastic stucco surfaces, so not being painted.