It was the prophet Jeremiah that spoke about the thirty pieces of silver NOT Zechariah.
Matthew
9.
|5119| Then
|4137| was fulfilled
|4483| what was spoken
|1223| through
|2408| Jeremiah,
|3588| the
|4396| prophet,
|3004| saying,
|2532| And
|2983| I took
|3588| the
|5144| thirty
|0694| silver pieces,
|3588| the
|5092| price
|3588| of the
|9999| {one}
|5091| priced,
|3739| whom
|5091| they priced
|0575| from
|5207| sons
|2474| of Israel,