Millions of Americans will be getting an extra stimulus check from the IRS soon. The agency is sending out 'plus-up' payments to people who did not receive the full stimulus amount they were eligible for. Most people in that category saw their income drop in 2020, making them eligible for a bigger payment. Instead, they would have received a smaller check based on their 2019 tax return. If you think you're eligible for a larger stimulus, the best thing to do is make sure your 2020 return is filed.