This money is referred to as “blood money” — money received for the life of another human being.
“Thirty pieces of silver” is also used proverbially to refer to anything paid or given for a treacherous act.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.