Sorry, my mistake. I was inadvertently thinking of what Microsoft charged PC manufacturers for pre-installation. The retail copies included extra charges to cover boxes, discs, distribution, the retailer's margin, support, returns etc.
Unfortunately I can't find a list of Windows retail prices, but originally Windows was sold much like an application. That is, it assumed you already had DOS installed.
From what I recall, the official retail was something like $99 and you could pick up a copy for around $80 or so. (Some programs came bundled with a run-time copy of Windows, though you couldn't used that copy with a different application.)
Windows 95 upped the price because Microsoft was charging for both DOS and Windows at the same time. On that basis, something like $200 doesn't sound wrong, and that's around the price Windows has sold at ever since. (Unless, of course, you buy a pre-launch offer.)
Software and hardware prices were generally much higher in the old days, of course.
On stability, I found both NT4 and Windows 2000 to be very stable. With other versions, they were stable if they were correctly set up on decent hardware, you only used Microsoft drivers, you were pretty careful, and you restarted every day.
I could usably run Win98-XP for about week. I would never find out how long I could run NT4 because I was dual-booting it ;-)
Eggs are fragile, but they generally don't break if you handle them carefully. It was much the same with Windows...