What currency does your world use?

I haven't fully designed the Vincharii empire's currency yet. I want them to have two types (if you will).

One is a standard inter-galactic credit, used to trade with other races and empires.

Their actual currency though, is used by Vincharii for Vincharii, all across their empire.

I haven't designed it yet, but hearing everyone's wonderful ideas and inventions on what they use always helps.

So, what currency does your world/people use?