This month is tough because there are so many expenses.
Moving house involves all sorts of expenses.
Children's education is costly in many ways.
It's an expensive time, so let's save money.
費用 is a neutral, broad term for cost or expense, whereas 物入り carries a nuance of unexpected or burdensome outlay.
Standard kanji spelling.
Alternate kanji form; less common.
Compound of 物 (もの, thing) and 入り (いり, entering, needing), literally 'things entering', referring to the need for money.