の足しに

as a supplement to

→ の
phrase Rare #42,911
as a supplement to Used when something helps add to or supplement an amount, resource, or effort. Often follows a noun or amount.
JA: このお金は旅行費の足しになる。
EN: This money will help cover the cost of the trip.

家賃や食費の足しにしろとでも?

What, you expect me to use it to help pay the rent and groceries?

— 最強のふたり (2011)

でも、白い魔法使いがついてるなにかの足しにはなるよね?

But with the White Wizard on your side, it should count for something, right?

— ロード・オブ・ザ・リング/王の帰還 (2003)

これは本を買うための足しになった。

This helped pay for the book.

それが音楽になんの足しになる

How does that add anything to the music?

— Pompo the Cinephile (2021)