You can usually find a body only with a box, charger, and spare batteries for ~$500 on CL and Nikon forums. So a "broken" d300 body only? You might find someone to pay you $200-300 but even that is questionable.
Well, anything that doesn't work as intended would be considered broken, wouldn't it? True, it also depends on severity of the issue, but most people wouldn't want to put up with a shutter like that. You might want to contact aps (or other Nikon repair service) for an estimate on the damage. Once repaired, it will be easier for you to sell the camera for about $450.