Sam-

You should update your profile, noting your location.
Where you are on this planet has something to do with market value of a double rifle.

Also, you're going to need to give a lot more information on this rifle in order to get even a ballpark figure on it's value.

Tell us what action type it is, if it's a SxS or an O/U how many triggers, if it has ejectors, what kind of sights, what condition it's in, how the bores are, how the wood is...

Then it's still possible that the thing's damaged and not evident from a photo or a casual look-over.

Post some photos though!
I'd like to see the Gaucher you speak of...

--Tinker