Federation credits are units of currency used in transactions with some Federation and non-Federation worlds or for goods and services that cannot be replicated efficiently. Although not a monetary unit in the classical sense, it makes exchanges with alien planets possible. (TOS: "The Trouble with Tribbles"; TAS: "Mudd's Passion"; TNG: "The Price")
When interacting with alien cultures, Federation citizens simply inform the aliens that they will be "paying" in Federation credits and the aliens get their true compensation through trade agreements between the two governments. Thus, Federation officers could buy drinks at Quark's Place without owning a single bit of latinum. (Star Trek: Deep Space Nine)
- Kirk stated that Starfleet had a lot invested in both he and Mr. Spock. In fact, Starfleet had 122,200-plus credits invested in Spock by the year end of 2267. (TOS: "Errand of Mercy", "The Apple")
- Uhura offers to purchase a tribble for 10 credits. (TOS: "The Trouble with Tribbles")
- Beverly Crusher buys a roll of cloth, and has her account on the Enterprise-D billed. (TNG: "Encounter at Farpoint")
- The Federation would have payed 1,500,000 Federation credits as a lump sum and then 100,000 credits every Barzanian year for the rights to the Barzan wormhole. (TNG: "The Price")
Behind the scenes
Ronald D. Moore commented: "By the time I joined TNG, Gene had decreed that money most emphatically did NOT exist in the Federation, nor did "credits" and that was that. Personally, I've always felt this was a bunch of hooey, but it was one of the rules and that's that." [1]