It looks like Patch 1.04 fixed the exploitable glitch that allowed players to make infinite money by buying sea shells and having them dismantled so you can sell the more precious contents. The merchant who sells the shells is no longer selling them, but he stands in the same spot in the square, presumably to mock you for no longer having the lucrative money-making scheme he once provided access to.
Of course, if there’s a will, there’s a way. Players have explored other exploitables, and it turns out that you can get a good deal if you sell to the right person. This video from YouTube channel Push Square shows you how:
Players will still end up back in Novigrad, but this time around, should head for the blacksmith. Have him craft several of an item that costs only a few resources. Now instead of items for crafting, you’re probably stuck with a handful of boots or swords that you would otherwise make very little money on. Don’t try to sell them to vendors in the immediate area, they’re sure to lowball you.
Instead, make your way to the seashore and visit the shopkeeper. He’s not exactly rolling in riches, but he does have some coin. Buy the cheap glass bottles he has, just to make sure he’s got money to buy your items with, then proceed to sell your bulk items to the shopkeeper at full price. It takes a little more effort than the last money-making scheme, but this appears to be legal in-game, and not a glitch like the sea shell merchant, so this probably won’t disappear with the next patch.
But what are you going to do with all those glass bottles you bought from the seashore shopkeeper? Sell them to the merchant in the square who refuses to sell you sea shells, of course.