Hope you are going to install extreme long-life bulbs in this fixture.
You don't say if a 1) heavy-duty chandelier/fan braced box exists there already or if just 2) a regular light fixture, or 3) none. If 1), then no extra cost for that. If 2), add about $100-150 to replace the box with one designed for heavy loads. If 3), then add anywhere from $150 to 400 to install a box, run wire to a new switch, and bring power to the switch.
As the other comment said, this is going to be a 2 person job, with scaffolding. Figure $75 scaffolding rental, about 1-2 hours labor depending on how much of a hassle the connection is, as some heavy chandeliers, fans and heavy lights have to be rewired to facilitate installation because they come with such short pigtails. Figure about $75-125/man-hour = $225-575 light installation from best to worst case.
Therefore, that number if already a heavy-duty box there, to max maybe close to $1000 for a brand new installation with power, switch, box, etc. If requires cutting into ceiling and walls for wiring, could be $150-500 additional in drywall repair and painting. Depends largely on whether access from above (open floor attic) is available to install box and wiring, or if it is going to mean cutting through ceiling and walls, etc.
Never thought a simple light could run as much as $1500 to install, did you, but it can happen, so be sure to get firm bids. I had one job once where this sort of installation was decided on almost at job completion - cost many thousands of $ to do because expensive decorative interior finishes were already complete, so siding and some flooring had to be removed to run the wiring and install the box.
Of course, does not include cost of fixture itself.
