Albert Barnes Commentary 2 Samuel 18:11

"And Joab said unto the man that told him, And, behold, thou sawest it, and why didst thou not smite him there to the ground? and I would have given thee ten [pieces of] silver, and a girdle." — 2 Samuel 18:11 (ASV)

Ten shekels - (About 25 shillings.) The word “shekel” is understood, as in Genesis 20:16; Genesis 37:28. See the Exodus 38:24 note.

A girdle - Girdles were costly articles of Hebrew dress, used to carry money (Matthew 10:9) and given as presents (1 Samuel 18:4).