The Federation uses money units, shortened to mus.  (Say it like ‘amuse’ without the ‘a.’)  They don’t use notes or coins.

Victor is like a bank.  If I wanted to give Hais 10 mus, we would tell Victor.  He would take the 10 mus from my account, and add it to Hais’s.

If Tony and I  want to spend our Federation money at home, Simon gives us £1 for every 1 mu.