around here (boston area), it appears that a nice box like that will go for 700$.
i say appear because, well, there is no sold history on CL like there is on ebay, so we really dont know.
i have a bunch of older snap-on boxes. i tend to buy the kr650/655 sets and kr290 sidecars.
from what i hear, the issue around here is that no one is buying old "small" boxes. they all want 72" wide boxes, not 35 (like i buy) or even, what, 55", like you have.
well, there are buyers, but they are all "bottom feeders", like me, i suppose. i pay 400$ for a 650 or 655 in good shape. less if it isn't in good shape. people list stacks around here for 1500$, but they sit there and sit there and eventually, after touching the ad for a few months to keep it active, it just disappears. did it sell? sure, that is possible, but i dont think it is likely.
i have noticed a lot of kr660's showing up around boston over the last year. i get the impression that "dad doesnt need it anymore". i dont know if that means that dad died, retired, moved to assisted living, or whatever, but i do know that if you are listing that box for more than 1000$, you are wasting your time. . . . . they are trying to sell it on CL because the only people who will buy it are the truck tool sellers, and they will only take it in on a new box. (i dont know what they do with them. if you are out there, sitting on one or more of these boxes, PM me and we can talk. i dont need more, but . . . . .. )
anyway, it is worth what someone in your area will pay. where you start is a combination of how much you think it is worth, and how long you are willing to wait for someone to agree.
and, from the look of it, special editions dont add to the used value. non-red boxes seem to be worth less.
good luck.
