The only way that you earn Nitrous is by working as a fisherman.
But since the fisherman job system updated, it's been a little harder, less and less people work as this job.
Thus the nitrous is now rarer than before, but the maximum price of Nitrous in F7 is still 10$, not changed.
So I suggest raise the maximum price to 20 or 25, so players would like to sell their nitrous for balance money.
Btw, increasing the limit of NOS price, won't break the balance to other job! Cuz the price is depends on players, if you think it's too high, don't buy it. in my view, 20 or 25 is not high at all. Cuz it's hard to get NOS than before.