Only Matthew gives the amount of money that Judas was paid to betray Jesus: thirty pieces of silver (Matthew 26:15; 27:3). How much was that? The term for “pieces of silver” is arguria. The Roman silver coin was the denarius. (The aureus was gold; the sestertius and dupondius were brass; and the as was copper).
What exactly would 30 denarii buy? In Egypt, it would buy half a year’s worth of wages for a day laborer. In Judea, the wages were higher (as were the prices) and so it would buy less. Still, it was a fair sum of money, about enough to buy a cow at the time.