He picked the ring up and stared at it absently, rolling it back and forth between his thumb and index finger.
Thirdly, ask the shopkeeper or ring up the manufacturer.
If I quoted him 1s.9d for American turps he would ring up a competitor in my presence and try to get a better price.
You may even do the same thing waiting for the cashier to ring up the sale.
A separate cashier may be the actual person to ring up the payment.