H&R made a number of models of single barrel shotguns. All were utilitarian hunting guns, and sold for quite low prices. While rugged and reliable, they still are bought primarily for hunting guns and prices range from $100-150.
BTW, the prices I and most others will give on these sites are the prices you might expect to pay at a gun show or to receive if sold to an individual buyer. In other words, they are retail prices; the price you would receive from a dealer is another story. Many dealers simply will not give anywhere near a fair price on a straight sale.
If you are selling guns and want to work through a dealer, the best route is a consignment sale. You decide how much you would like to get, and he adds his percentage. As an example, if the retail value on a gun is $500, I might tell the dealer I want $400. Anything he gets over that is his, but typically, he would sell the gun for the $500 retail value. Another way is to let him set the selling price, then he takes a percentage and gives you the rest. All of this should be worked out, in writing, before turning a gun over to a dealer to sell.
Jim