I paid a seller about $1200 for a Brown & Sharpe "Universal Milling Machine" of the "early" pattern, i.e. no over-arm. Complete and in "as used but removed" condition to include some centers and a full set of gears (on the shelves inside the door.)
Brown & Sharpe Universals are considered a "landmark" milling machine for many reasons, not the least of which it brought universal mills into common use (Yes Rob L., universal did exist among many builders prior to 1862, but Brown & Sharpe brought it to uniformity and general acceptance as a "toolmakers" milling machine. And it also suited "their brand" of involute gear and twist drill milling cutters - which is where they REALLY made the money once they got accepted.)
Anyway, most makers after 1862 brought out their own "universal" milling machine in emulation and competition, even Pratt & Whitney, which they did in a "smaller" version first (which stands on the same four legs as their 6" shaper.) Only a little later did they come out with a direct competition to Brown & Sharpe's machine in size and application.
Another of these early Brown & Sharpe machines I saw in the mid-country, which listed for $150 - condition good (i.e. indoors and not rusted) but missing parts of the table drive. I turned it over to an acquaintance in the hobby. He snapped it up as he was looking for that "landmark" machine and either felt himself able to duplicate parts, or not concerned that it wasn't complete.
So perhaps I have "bracketed" these pattern of machines: possibly as low as $150 or as high as $1200.
If I were to put a "craigslist" number on this Pratt & Whitney myself, I might put it at $400. A complete Burke setup with a good assortment of cutters can run you up to $1K, but most are less complete, and even "plug & play," can sell for as little as $400 - and these not rusted. But less "landmark" certainly.
Scrap it would probably be worth $150 to $200. So maybe start at Craiggie $400 but be willing to dicker for "interested parties?"
And interested parties is perhaps the key. Perhaps rather than money value received, one gets satisfaction that what this machine represents is now more likely to survive, if it's into the right person's hands, and interests.
There is (or should be) a sense of commitment to "custodianship" here. Machines of this ilk are unique now. In fact ANY flat belt machine is a throwback to a previous age - they are only made now "custom" and for enthusiasts. Thus as an owner of this or any similar machine, one has to consider "it was still surviving until YOU arrived" - and it will only be replaced at extreme cost and interest. If indeed you have to end it at the scrapyard.
I have ended machines at the scrapyard. But that was back then when my interest in the machines was exceeded by my ability or knowledge or where-with-all to deal with them long term. Possibly before even the Internet which is the knowledge part. And I dealt with them in the best manner possible for me at the time. And in a couple of cases it was not pretty. And today with more where-with-all - and the Internet - I would do differently.
Learning all the time...
We do (or should) have a responsibility to our industrial heritage. Elsewhere I have opined that Americans are more or less "slaves to progress." Anything which is not fashionable or current, or "earns its keep" is somehow a luxury to keep around for Americans. And the usual consensus is that the past is a luxury we can't afford. Life is that competitive for Americans. The Brits have done a MUCH better job at their industrial archaeology and preservation. Not that like the Brits I advocate laws to make it happen - I don't. But we should be doing this because "those who forget the past...etc, etc.") And our own long term self-interest.
If everything goes to "progress" - what happens when you progress yourself into a "technical dead-end" and the underlying "field of action" changes? If all machines operate from grid-power, what happens if for some unforeseen accident, or intention the grid is NOT available? You're up sh*ts creek. And this said by a former power plant engineer whose life's work was devoted to keeping the grid up.
Anyway, this I think the big picture here. Your personal picture will no doubt be different.
The best of luck in any case.
Joe in NH