The Saver's Credit rewards lower-income workers for contributing to a 401(k), IRA, or other retirement account. Depending on your income, you can claim 10%, 20%, or 50% of up to $2,000 in contributions ($4,000 if married filing jointly). The credit is non-refundable. Many people who qualify don't know it exists. Check the IRS income limits each year, as they adjust for inflation.