Just how many C-Bills are in a metric ton anyway?
Depends on the size and denomination of the bill.
A square meter of printer paper is, IIRC, about 80g. So a metric ton of printer paper should be 12,500 square meters.
Assuming that C-Bills are printed on paper that weighs the same, and that each bill is about 100 square centimeters (1/100 of a square meter), and the average denomination is 10 C-Bills, we´d have... *sounds of frantic calculator-button-punching* 12.5 million C-Bills.
Which, admittedly, isn´t all that much to equip a merc unit with.