My guess:
- Judas was paid 30 pieces of silver for the life of Jesus
- Micah stole 1100 pieces of silver and returned them (Judges 17) and his mother made an idol out of 200 of them.
So that 1100 pieces of silver bought an idol, but 30 bought something greater, salvation.
Am I close?
[Note: I had to google for the passage in Judges]