I’m with Mrbb on this - I’ve worked in a few shops and made a business of buy/sell/trade guns for several years. Sitting on a rifle like that for 2 years is a sign of a poor businessman, letting it go below market value to avoid further inventory cost on it is yet another.

Inflation is a powerful thing. We remember Marlins sitting on the rack for $200-250 not so many years ago, and wonder in awe how they might be priced so high today. Inflation over 20 years adds 50% in “dollar for dollar” cost, then you add the value of a JM stamp reputation versus a Remington built rifle, and consider that leverguns have shifted from being a staple firearm to a boutique status - they easily bring far more than their pre-2000 retail price might suggest. I’ve enjoyed this fact myself, as I had a handful of pre-Remington Marlins and pre-Miroku Winchester leverguns in my safes which tripled or quadrupled my money when sold. Rough shape is rough shape, but we’re not playing based on their retail prices any more.

Incidental to the timing of this post, I picked up a 35rem JM stamp Marlin a few months ago as barter against building an AR upper. I haggled a $400 value to the rifle, negotiating its sale for $550 to the new owner even while I was negotiating its acquisition from the original owner. I only had it in possession for 3 days.

Commodities are worth what a person is willing to pay. Tiffany & Co sells a gold plated bookmark shaped like a 2.5” long paper clip for $1500... There’s no real trick to it - know your market’s price tolerance for a product and know how to move products at profit. Sometimes you get stuck, most of the time you don’t.

But the OP story really just sounds like a local shop owner who needs to buy a computer and learn about online selling. He could get $400 for a 35 Rem Marlin without breaking a sweat.