Earnings
noun
稼ぐ is "to earn income." This is the noun version. It's just earnings, the things you earn.
The reading comes from 稼ぐ.
稼ぎがそんなに多くないので、何によくお金を使っているか習慣を見直して節約するために家計簿をつけています。
Our earnings aren’t very high, so I keep a budget account book to look at our spending habits in order to save money.