found a Crosman 600 LNIB

[randy_68]

But not sure what these are really worth. Prices are all over the place from what I've found. The box on this one looks pristine as does the gun. He told me it hasn't been shot in years and figures it will need a seal kit installed. He wants me to make an offer.

[BrushPopper]

Seal kit from Baker'll set u back $40.

I'd consider $100 a steal, for one in that shape... offer $75. If the outlet/stem seal is bad, cost of repair would likely be more

[45flint]

Offer what you feel you want, LNIB would be north of $200 working, don’t let it get away.  There are a lot out there but not that many LNIB.  Also you may get lucky and with lub seal it? 

[the fuse]

If you are the only one making an offer, start low......$100 is truly a steal. If there are others involved $100 will get nothing but a laugh. Hope you get it. 
Definitely give it a good drink of ATF or Pelgun oil, or Secret Sauce and let her sit for a day or so before doing a reseal. It might surprise you with a couple years of good shooting before she blows.

[unionrdr]

Sort of related, I saw two Crosman 622's on EBay for bids. I was looking for others, and saw them. One looks very nice indeed. Still there today so far. And a NOS 760-D Pumpmaster with the original box, manuals, and optional scope!!! High bid only $24.75! I don't have enough cash to spare, having bought the 760 Pumpmaster variant 7, the 5-gun rack on Amazon, and made an offer on a 66 Powermaster. That NOS 760 is beautiful! Kinda wish I hadn't bought the gun rack, and bid $30 on the NOS 760!

[DRose]

If it is original condition chances are the grease has solidified. Trigger parts can be damaged. Be careful with your gem. (You are going to buy it)