The OP has not told us where he/she is. None of us have seen the site. Maybe the home is in the Hampton's where you probably need a Mercedes or Porsche to haul things away. Perhaps it is a lighthouse keepers dwelling and you need a merchant ship to handle tides and wave actions to get the windows delivered. While the price seems high how much so is really relative and we do the OP no favors with price related comments. I hate it when people offer estimates on this site. It is not fair to the posters nor the contractors working in their areas because they are, for the most part, irrelevant.
Here is the official post about estimates on this site. Essentially the OP needs to get some from people that can actually visit and adjust for whatever local market conditions, hauling practices and the condition of the home where the windows are to go.
Reminds me of my first roofing quote for a 1,900 sq./ft home in Texas. First guy wanted 12k. Fortunately, I would never agree to something for that price (even if it was actually a good price) without competitive bids. Ended up paying 5k and another hail storm later paid 6k on same house. If price seems too high then shop around.
If you're mostly replacing the windows for A/C, look into a mini-split or ductless A/C unit. You only need a 2-1/2" hole in the wall, and they are way more energy efficient than window units. The heat pump models will heat as well, down to -5F.