Try e-gunparts.com
$500+ depending on condition
Single barrel, under $100. Double-barrel up to $200 unless heavily ornamented.
Turn of the century, inexpensive.
Between 35-60 dollars.
Typically, up to $250. Rare and heavily engraved special versions would bring more.
Hopkins and Allen made double barrel shotguns from 1902-1909,they made single shots from 1887 to the early 1900,s.they also made the 38xl and 44xl drop block shotguns from 1890,s thru 1914.
Not listed in any reference I have seen.
numrich
There is no serial number data for the Company Hopkins and Allen in the private sector available.This firm was in business from 1867-1916.No laws required serial numbers at that time,and those that were marked with a serial number have no records remaining today.If you have a single shot shotgun,these were made from 1887-1902.If the markings say Hopkins and Allen Manufg.Co.Norwich,Conn on the gun then this was made from before 1896.If you have a double barrel shotgun,then these were made from 1902-1916,when they went out of business.
I have a nitro hunter 12 ga serial 555281 $50 for the whole gun
Start with gunpartscorp.com - they sometimes have Hopkins & Allen parts