a window that is nailed to a frame is for new construction only and not replacement, typically for a replacement that frame is saved and just the window is seperated from it. In my area it runs about $120 to install a replacement window with minimal trim on the inside just to finish the new window to the old frame-and none on the outside, with a exterior wrapped -the cheapest quote i got was about $200 per window ,that included them removing and disposing of the the old window and that was with the purchase of 8 windows – i was told any less than 5 windows and the price per window goes up .
but you would have to add to that price if you wanted new casing on the inside also – i was planning on keeping the interior casing so i cant help ya with a price for labor but the wood alone is costly so id imagine another 70-100 per window but thats just a guess.
ps im in CT and labor rates are high here, but home depot has a special for a window installed for 299 (includes window and minimal instalation) if your on a budget it might be worth looking into.