A Section 8 housing voucher will pay for some or all of your monthly rental payment. The exact amount that is covered will depend on the Fair Market Rent in the area, the payment standards created by the PHA and the size of the unit to be rented. In general, tenants must spend at least 30% of their monthly adjusted income or 10% of their monthly gross income on rent. Their voucher will cover the remaining portion. Tenants with the greatest financial need typically get the largest subsidies.