During the Star League era (2571-2785), the Star League Dollar (SL$) was used as a common currency throughout the Inner Sphere, standardized on the amount of germanium in Fort Knox on Terra, the vital component in Kearny-Fuchida Drives. Once the Succession Wars broke out, each of the five Great House leaders began issuing currency bearing their own likeness. These currencies would later become known as House Bills (or H-Bills), the value of which was based on the house's economic fortunes. The Star League scrip was eventually discontinued.
The C-Bill originated from early ComStar's Letter of Credit, which detailed the value of ComStar's communication services to the Great Houses and the public. Approved in 2835, the C-Bill was intended as a method of payment for those services, its value based on a fixed amount of ComStar service, transmission time, or delivery distance. Because of the uncertainty of the exchange rates for H-Bills, many mercenary units would request payments for their contracts be in C-Bills, to ensure a consistent payment basis. As a result of this and interstellar trade in general, the C-Bill became a common secondary currency throughout the Inner Sphere and the Periphery, in many places replacing the local H-Bills.
After the collapse of the HPG Network in the Dark Age era the C-bill's value plummeted into worthlessness as the backing of the currency was rendered functionally non-existent forcing use of H-bills or barter to replace the now useless currency.
C-Bills are generally used in an electronic format, but are often commonly encountered as paper notes in denominations of 1, 5, 10, 50 and 100 units. Within territories administered by ComStar, coins called demis are issued. In external areas, local currency is used for sums smaller than 1 C-Bill. 
In 3025, the exchange rates for the various H-Bills and the C-Bill were as shown in the table below. This is a relative comparison only, as actual exchange rates would have varied daily. It should provide the reader with a view of the relative economic successes of the various houses.
|Game Year||Source Year||Current |
|3025||1986: $5.00 ||2021: $11.93|
|3052||1991: $5.00 ||2021: $9.72|
|3062||1999: $3.00 ||2021: $4.78|
- MechWarrior, Third Edition, p. 180, "Local Currencies and Exchange Rates"
- ComStar, p 12, "Operation Silver Shield"
- MechWarrior, Third Edition, p. 182, "ComStar"
- Classic BattleTech RPG, p. 182, "ComStar"
- US Bureau of Labor Statistics: Consumer Price Index Inflation Calculator
- MechWarrior: The BattleTech Role Playing Game, p. 104, "Currency Conversion Chart"
- MechWarrior: The BattleTech Role Playing Game, Second Edition, p. 145, "Currency Conversion Table"
- MechWarrior, Third Edition, p. 131, "Exchange Rates Table"
- Classic BattleTech RPG, p. 131, "Exchange Rates Table"