general questions about fur trade artifacts

[glass half fool]

I have known for a long time that the fur trade industry was an important part of the history of North America . But it was only by finding this forum that trade artifacts from that era existed .The Hudson Bay Co. was one of the largest companies in the world during those years . And John Jacob Astor was one of the richest men in America when he died in 1848 and much of that came from the fur trade industry .One of many questions I have where the tokens currency per say issued by the different fur companies .If so how where they valued ?It is general knowledge that the trading companies ripped off the men supplying the pelts by over charging for goods .Where the tokens given to the trappers in exchange for there catch and than it turn used to buy goods for the next season .Any info would be very much appreciated .