Idea on fair market value on old King Silvertone 2B

[ttf_Chris Dearth]

Question for you guys.  The shop I work at came into an early 1940's King Silvertone 2B. I'm interested in buying it for myself, but the owner wants to know what fair market value it is on it. 

-It needs a trip to the slide doctor.  Has dent and alignment issues.  Barely playable.  Chrome on inner slides is in great shape.

-Has dents in tuning slide and bottom crook.

-Lots of tarnish obviously.  Can't address the plating condition until that is removed.

-No original case or mouthpiece.

I've seen eBay asking prices for pristine ones (which can range $2000-$3000 depending on seller). 

What would be a fair price for me to buy it from him considering the above info?  Any info is appreciated.

[ttf_Euphanasia]

Closed Ebay listings show crazy variations in price.

http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=king%20silvertone%20trombone&LH_Complete=1&LH_Sold=1&rt=nc&_trksid=p2045573.m1684

Over $500 for just a bell flare, down to $360 for a complete horn from the '20s (which I think was a steal.) Yours is more desirable than that '20s horn because it has a more modern slide design.  Also, it has the gold wash on the bell engraving. I'd put it at $650-$850 as fair market value.

[ttf_Exzaclee]

'40's 2B silvertone - given your info and the pics, I concur with Euph. 6-850 in current condition.

[ttf_Exzaclee]

'40's 2B silvertone - given your info and the pics, I concur with Euph. 6-850 in current condition.