We need to find alternate currency....
In prison we used stamps (FMC Lexington) and/or cans of mackerel (FPC Ashland). (I kid you not, all the nouns in that sentence have been double checked.)
1 stamp was 25 cents, yes you could go to the commissary and buy stamps but at that time a stamp cost 32, or 38 (or similar) cents, we all just considered a stamp to be worth 25 cents.
1 can of mackeral was a dollar, and cans sold for a dollar at the commissary.
Now in both of those cases, we were able to use stamps or cans of mackeral as currency, because they were obtainable at a set price and consumable. (people maild lotsa letters, and the weightlifters ate lotsa cans of mackeral (cheapest source of protein in the joint))
Best thing I can think of for you would be to buy large scales, but there is risk as we all know is mod 9 coming, and god knows what the designers have in mind then.
If only the game designers would take the blinders off... Why does a gem sell for 1/10ish (depending on haggle) of it's base value, if they made them a constant, problem would be solved. Why cant they just add a npc that buys and sells marks of boldrin at the fixed price of 100kpp each.