As one might imagine, the CharLoft being an interdimensional watering hole, people tend to attempt to spend all manner of currencies therein. Although the CharLoft does not run a currency exchange, they do accept a wide variety of currencies from various worlds. In most cases, the estimated value of the currency is based on the amount of use the barista expects to get out of it (and what they expect to get when they exchange it with the boss later), as well as to a lesser extent what it is worth to the individual spending.
All prices in the CharLoft are based around the 2012 American dollar, although other major currencies are accepted readily. Currencies that are generally unidentifiable are given effective value based on their material value and on the barista's whim, though usually the exchange rate is not ideal, and better deals can be made with gullible or opportunistic patrons.
Many baristas tend to use the Barista's Handbook for advice when converting currencies; this provides a reasonably fair exchange rate, but tends to err on the side of the house. As a rule, at best, non-American currencies are accepted at half the value they would have back home; devalued currencies (like the 'gold pieces' of various gaming or fantasy worlds) tend to be accepted at incredibly deflated values (one thousand units to the dollar or more.)
For this money, people can acquire nearly anything – though most of the Char Loft's offerings are related to its purpose, in theory, one can ask for nearly anything and expect to at least have them look to see if it can be acquired, whether it be a lamb sandwich or an anti-tank mine. In practice, the prices on these goods are often inflated in relation to how disconnected they are from the Char Loft's primary function of coffee-shop food and drinks, but if you really need something, chances are good that the Char Loft can sell it to you if you have the cash.
The Char Loft does have its own currency, though – special tokens that are equivalent in value to $0.05, $0.25, $1, $5, $20, or $100. These tokens are made out of an odd black metal with runes all over it, and are accepted without comment as 'good-as-cash'. Notably, the vending and arcade machines upstairs can accept these tokens (counting their value appropriately), and the barista can make change in these tokens if asked. (Values under $0.05 are rounded down, as the CharLoft only accepts exact change - or currency worth equal or more than the value of the goods procured.) Typically, Loftian Currency is denoted as $1 LC per unit.