you get what you play for

I have a 100 year old house with the original single pane windows. We had at least 5 companies give us a estimate.
The lowest was $5000, he offered we could pay cash. We passed his product looked like crap.
Three others were pretty ($10,000) close including Costco. We wound up with a company called Magic Windows
They have no cranks just handles and you push the window out. They're pretty cool. They came in at $17,000 for 8 windows. My g/f grinded the sales guy down to $12,000.
The best part is we can't hear any thing outside any more.

My house is just over 50 years old. Most of the windows though are part of an addition on the North end where the living room was extended out and the entire walls are all windows. Ten total.

They are single hung with double layer glass and most were cloudy when I bought the place 24 years ago. At the time I was working in an industrial park and there was a glass place a couple doors down so I took each window out one every week or two to him and he changed them out to just a single pane. They could still need an upgrade because they don't raise up and lower all that great anymore plus the gaskets aren't that great.

I did have the big one in the living room changed out by a local window/door place after I first moved in. It was those patio windows and now I have two single hung there.

I will probably try to use something from HD when I do mine....something like this:

37 in. x 63 in. Single Hung Aluminum Window - White

I'm buying double glazed from now on. I love them.

But mentioning this just out of interest. In my bedroom there was old 3mm glass that had got etched from being blasted by storm driven sand. I replaced it with 5mm glass. The 5mm glass was weird stuff. Hard to cut and VERY heavy. I've handled lots of 4mm glass but this stuff weighed twice as much. But the interesting thing was the noise dropped off by about 75%.