100 C-notes

TENG

Think of how you might say "10,000 yen" in Japanese slang, then drop a zero.

"100 C-notes" is slang for $100, since "C-note" is a common term for a $100 bill. The word "ten" sounds like "T" and "G" is the abbreviation for "grand," another slang term for $1,000—so $100 is one-tenth of that, or "T" plus "G" (but here shortened to "TENG" for the crossword). It’s a playful mix of slang and letterplay to fit the puzzle’s answer.