The Carthaginians are credited with inventing sale by auction, and they were famous for it. They even traded with people with whom they had no real contact, as described by Herodotus of Halicarnassus (about 430 B.C.)

"The Carthaginians also say they trade with a race of men who live in a part of Libya (Africa) beyond the Pillars of Hercules (Straits of Gibraltar). On reaching this country, they unload their goods, arrange them tidily along the beach, and then, returning to their boats, raise a smoke. Seeing the smoke, the natives come down to the beach, place on the ground a certain quantity of gold in exchange for the goods, and go off again to a distance. The Carthaginians then come ashore and take a look at the gold; if they think it represents a fair price for their wares, they collect it and go away; if, on the other hand, it seems too little, they go back aboard and wait, and the natives come and add to the gold until they are satisfied. There is perfect honesty on both sides; the Carthaginians never touch the gold until it equals in value what they have offered for sale, and the natives never touch the goods until the gold has been taken away."

This description of "perfect honesty" on the part of Carthaginians may surprise some, since the enemies of Carthage (the Romans and Greeks) described them as cheats and liars; even today you can find in the dictionary "punic faith" as meaning dishonesty, yet there is little evidence that they were dishonest in trade. Common sense dictates that they could not have traded long if they were dishonest as a common practice.

The intransigence on the part of some natives to trade with Carthaginians in person may be related to their Tyrian cousins making slave raids. The Carthaginians certainly had slaves, as well, but apparently did not go on slaving expeditions, at least not after about 500 B.C., as testified in their first treaty with Rome, which mentions coastal raids.

Warfare in ancient times was a different affair from today, and was seen as an important source of booty and slaves. Captured enemy soldiers might be ransomed back to their homeland or even exchanged, the going rate being two "mina" (a mina was equal to 50 shekels, or about 0.944 pound) in silver per soldier - (which is the price Hannibal demanded for the captives taken at Cannae) but if their homeland refused to pay or could not, they might be sold into slavery. One of the earliest accounts of a naval battle records the fate of the sailors of Phocaia taken captive by Carthage and her Tyrrhenian (Etruscan) allies - the Tyrrhenians killed their share of prisoners by stoning, while Carthage sold their own share into slavery. Enemy people too could be taken as slaves and sold, especially in the case of the taking of a city that did not surrender right away.