Kautilya's Arthashastra 2.21.7

2.21.7

dhvajamūlopasthitasya pramāṇam arghaṃ ca vaidehikāḥ paṇyasya brūyuḥ "etatpramāṇenārgheṇa paṇyam idaṃ kaḥ kretā" iti //

The merchandise being placed near the flag of the toll-house, the merchants shall declare its quantity and price, cry out thrice "who will purchase this quantity of merchandise for this amount of price," and hand over the same to those who demand it (for that price). When purchasers happen to bid for it, the enhanced amount of the price together with the toll on the merchandise shall be paid into the king's treasury. When under the fear of having to pay a heavy toll, the quantity or the price of merchandise is lowered, the excess shall be taken by the king or the merchants shall be made to pay eight times the toll. The same punishment shall be imposed when the price of the merchandise packed in bags is lowered by showing an inferior sort as its sample or when valuable merchandise is covered over with a layer of an inferior one.