en_tn/2sa/24/24.md

I will not offer ... anything that costs me nothing

This can be stated in a positive form. Alternate translation: "I will only offer ... something that I have paid for" (See: rc://en/ta/man/jit/figs-doublenegatives)

fifty shekels

"50 shekels." A shekel is 11 grams. (See: rc://en/ta/man/jit/translate-numbers and rc://en/ta/man/jit/translate-bmoney)