Save America's Main Street Act This bill allows (1) certain small businesses ($1 million or less in gross receipts and not more than 50 full time employees) a tax credit for the lesser of 30% of their gross receipts or $75,000 for the first taxable year beginning in 2020, (2) deferral of estimated tax payments for such businesses, and (3) certain small business employers a payroll tax credit for 50% of wages paid to their employees unable to work due to COVID-19 (i.e., the coronavirus disease 2019).