Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 9 months ago

If you have any amount which remained after spending your usual lawful  livelihood expenses, Khums will be obligatory in that amount, no matter how small it is. If all your income is spent on your usual lawful expenses and nothing remains, then no Khums on you.