Just got this mission pop up on my feed, at first glance, it seems reasonable: $750 isn't that much. Then I look again, they want it in dimes: 7500 coins. I can fit 600 rolled coins in a large box and 3640 in a XXL moving box, that's 13 large boxes or 2 XXL moving boxes to fit the entire order. That's 2k more than my entire coin inventory in a denomination I don't even keep: I use those to feed the washing machine.
It's kinda obvious what's happening here: the mission generator starts by randomly choosing a set target value for the mission, then it randomly chooses whether it's going to be an "any denomination" mission or request one in particular. At no point does it "sanity check" by circling back to figure out whether the amount of coins it's requesting is a reasonable figure.
The solution to this (and my suggestion) is to flip the script on the mission generator: start by choosing a target number of coins or bills from a sane range (in multiples of 20 for coins or 100 for bills, so you don't need to mess with partial stacks), then randomly select a currency and denomination, then multiply the first number by the second to get the final value of the mission. In the event of an "any denomination" mission, assume the average bill/coin someone will use is the second highest available ($50 bill, 1 euro coin, 100 yen coin, etc.) and base your numbers on that. It's less of an issue with bill missions because you're giving the player the money, but if we're expected to keep an inventory of change to fill the occasional mission from The Master of Coin, it should be a reasonable amount.