Well, there's a bit more to this than meets the eye, so to speak!

First up: condition is everything. Particularly bore condition. Most other things can be fixed, albeit for a price.

The heavier chamberings command a premium, from .450 up, but the .375H&H is useful. ...although some might question the rimless or belted cartridge as a sensible double rifle choice.

Ejectors are preferable for the hunting field, also commanding a higher price.

Having said all that, thirty-five hundred would be a good price for a nitro double in VG condition or better, with no issues.

...if you can get it for that!