Hyperinflation.

[GhostMouse]

The fundamental flaw with any attempt to revamp the credit value is that demand never changes, prices are always stable, anyone can make the same runs over and over and be guaranteed a huge payout, even if everyone in the universe is filling that same demand.
So, the money is essentially generated from nowhere, because the benevolent buyers never get tired of goods. Even if you get rid of all the money in the system right now, and scale everything down, in 6 months time you will still have the problem of too much money in circulation.
Unfortunately the only solution to this is of course a dynamic changing market for goods and services based on player and NPC actions. Jobs need to be able to dry up, planets cannot be terraforming forever and require the same goods indefinitely etc. Its just not possible in freelancer to implement an actual economy.

The one thing I can see as limiting inflation is taxation. Ive seen it work in other games (chosen space for example) and lawful citizens must pay a healthy chunk in taxes, money that essentially disappears from the world but makes sense for governments to collect. It would be collected on a monthly basis and be either automatically withdrawn by the house governments of the player's home birth or be a voluntary thing, where not paying has consequences on player relations with government factions.