For most of us these days the answer is probably, "Not much." But even when there is something, at least for those of us living in the United States, figuring out what money you have isn't too difficult. Legal tender here is basically United States currency, with the occasional odd Canadian coin tossed in for those of us in the North. Lately, even our neighbor's small coins are being rejected.
Figuring out "what was in your wallet" wasn't always quite so easy. In our time period, the eighteenth century, there was a plethora of currencies in use. Of course today there are dozens of currencies, but they aren't circulated nor used world-wide.
In establishing a personna as a clerk in the fur trade, I've pretty much thrown myself into the study of eighteenth century finance (and its antecedents), accounting, currency and exchange, and so on. A clerk in the fur trade, supervising a trading post in North America, probably would not need as extensive a knowledge perhaps. But, somewhere, someone had to have knowledge of and be keeping track of the various components of the financial underpinnings of trade between the Canada, London, and the rest of the world.
As I noted above, there were a number of currencies in play: French, English, Dutch, German, Spanish, and on (much later U.S. currency). Each had a rate of exchange in play by which one currency was measured against the other (usually figured upon the amount of silver in the "hallmark" coinage, shilling, pound, livre, ecu, pistareen, etc. whether or not that "coin" actually existed or not). Think of the "exchange rate" between Canadian and US dollars, and its variability and you will have some sense of what is involved, then multiply it by 6 or 7 different currencies traded or used for payment.
Add to that a perennial coin shortage, discussions in other message boards notwithstanding. Coins did circulate, but the availability was more famine than feast, whether in Canada, England, or elsewhere on the Continent or North America. There was a constant competition to manipulate the exchange rate in order to attract coins, and governmental decrees to prevent the export of coins and metal.
In 1788 the Quebec customs collector noted that, "It is very rare I receive at my office either Bold or Silver . . . I generally accept notes." (in "Money in Canada", McCullough, p. 78) In 1792 three fur trading partnerships (Phyn Ellice & Inglis, Todd McGill & Co., Forsyth Richardon & Co.) were prompted by acute coin shortage to declare they would establish a bank (the bank ultimately failed).
These "notes", bills of exchange or commodity notes or other paper tender, also had their own exchange rate, whether drawn on London, New York, Canadian concerns, and discounts depending upon the length of the note before being redeemed.
All of these factors and more, could make the life of a simple clerk, or even a trader or partner increasingly complex as they sought to negotiate profit and loss on their business.
From time to time, I'll revisit this issue in some specifics as it may relate to one project or another in which I'm involved. Some very good references, though, on currencies, exchange rates, coinage available (and the coin famines) are: "Money and Exchange in Canada to 1900", AB McCullough, Dundrun Press, Toronto, 1984; pretty much anything by John McCusker though "The Economy of British America", U of No. Carolina Press, Chapel Hill, 1985 and "Money and Exchange in Europe and America 1600-1775: A handbook" UNC Press, Chapel Hill, 1978 revised/reprinted 1995.
Final note, especially for you fur trade reenactors: What coins, if you had them (and being in Upper Canada, so named after the division of Quebec in 1791, why would you need them? You wouldn't; barter and company book earnings/debt is the "currency), would you most likely have in latter eighteenth century?
British coins, you say? Nope. How about the French écu and the Spanish pistareen? Yep. Those were the main circulating coins. There's some backstory there, but it's complicated and more than you want in this post.