Walking into a neighborhood coin shop with inherited gold produces an offer that can look arbitrary. It is not arbitrary, and the arithmetic behind it is short enough to follow.
The shop is a middleman, not the final buyer
Most storefront shops do not melt or vault metal for long. They accumulate purchases and sell them onward to a regional wholesaler or refiner, often within days.
That means the shop's own selling price is already known to it: the wholesale bid it can obtain for your item. Everything it offers you has to sit below that number.
The gap between the two covers rent, staff, insurance, the shipment to the wholesaler and the risk that metal prices move while the parcel is in transit.
Form matters more than weight
A widely recognized bullion coin can be resold intact, with no processing at all. The wholesaler will bid a tight price for it, so the shop can pay close to that bid.
Broken chains, dental gold and unmarked items must be assayed and refined before anyone knows exactly what they contain. Refining costs money and returns less than the gross weight suggests.
So two items of identical weight draw very different offers. One is a finished product with a market; the other is raw material with a processing bill attached.
The shop is quoting against a moving number
Wholesale bids track the futures market continuously through the American trading day. A shop that quotes you in the morning is quoting against a price that will not hold all afternoon.
Because of that, most offers are good only while you stand there. Shops that hold a quote open for days are taking market risk and will price that risk into a lower number.
Volatile sessions widen every offer in the country at once. On a fast-moving day the wholesaler itself widens its bid, and the storefront can only pass that along.
Volume changes the math quietly
Fixed costs per transaction fall as the transaction gets larger. Shipping one insured parcel to a refiner costs roughly the same whether it holds a few ounces or many.
That is why a larger lot often draws a proportionally better offer, and why very small sales sometimes draw an offer that seems insultingly low relative to metal content.
It also explains why some shops decline small scrap outright. Below a certain size the transaction cannot cover its own handling.
What a second quote actually tests
Getting a second offer the same day, from a shop of similar size, holds the wholesale bid roughly constant and isolates the difference in margin. That is a fair comparison.
Comparing an offer today against one from last month tests nothing, because the underlying metal price has moved in between and you cannot tell which variable changed.
Asking a shop to show the wholesale bid it is working from turns an opaque number into a checkable one, and established shops generally will.