IMO the markup was simply the seller doing the work to buy inventory, photograph, and market it. They should get paid. They took a financial risk on the inventory, then used their time, equipment, and skills to photograph and re-market the piece. I'd want a lot more than 20-30% for putting all of into something as well. - I work in an industry where we don't touch a project if we can't get over 10X our cost on the goods. That other 90% goes to the work like he did, commissions, salaries, profit, etc.
My hoard of '82s is up to 204! 218 BC x 1, 118 BC x 3, 18 BC x 1, 82 x 1, 182 x 1, 282 x 2, 382 x 1, 582 x 2, 682 x 1, 782 x 2, 882 x 1, 982 x 4, 1082 x 1 1182 x 8, 1282 x 2, 1382 x 1, 1482 x 5, 1582 x 13, 1682 x 15, 1782 x 57, 1882 x 49, 1982 x 33