In this area, $500 - 750 if the installer provides the materials.
I agree, do it yourself and some help for the heavy stuff. Hire a few guys from out in front of Home Depot for 5 or 6 hours to dig the hole and install the pole. Provide them with 10+ bags 80lb cement, 2 or 3 bags of gravel, 10+ foot pole with tabs or rebar welded on 1 foot up from base and a post level.
What you are getting into: Sight survey for the most satellites if you have trees or buildings to the SE/S/SW. Dig a 3 - 4 foot deep hole 3 foot across in the shape of a water drop. This is to prevent the frost line from shifting the pole. Dump two bags of course gravel in the bottom of the hole for the pole to sit on. Place the pole in the hole and fill the hole with cement. Resist the urge to make a slab on top, keeping the top of the cement at or slightly below the soil line. This will keep the frost heave from moving the pole during deep freezes.
The knowledgebase is here if you want to give it a try. Just remember that the pole must be absolutely plumb and level!