This is a rhetorical question. You can translate it as a strong statement. AT: "This perfume could have been sold for three hundred denarii and the money could have been given to the poor!" (See: [[rc://en/ta/man/translate/figs-rquestion]])
You can translate this as a numeral. AT: "300 denarii" (See: [[rc://en/ta/man/translate/translate-numbers]])
# denarii
A denarius was the amount of silver that a common laborer could earn in one day of work. (See: [[rc://en/ta/man/translate/translate-bmoney]])
# Now he said this ... would steal from what was put in it
John explains why Judas asked the question about the poor. If your language has a way of indicating background information, you can use it here. (See: [[rc://en/ta/man/translate/writing-background]])
# he said this, not because he cared about the poor, but because he was a thief