We have a double barrell belgam steel shotgun late 1800 can you tell me its value?

Value could be anywhere from $25 to over a thousand. Depends on WHICH shotgun, and on its condition. Sort of like "I have Ford car. Its blue- what is it worth?". There are just too many variables for us to give you an accurate answer. Your best bet will be to have a gun dealer examine it. Inexpensive Belgian made shotguns from that time frame were sold by Sears, hardware stores, etc for a few dollars. Many of these were made for black powder shells ONLY, and should not be fired with modern ammunition.