You should not receive less than the minimum federal wage per hour.
This is the law in the whole country, but there are a few exceptions. You can contact a lawyer to find out more about the exceptions.
It does not matter if you are paid by piece rate or by quantity. It does not matter if you do not have papers. Your employer always has to pay you the federal minimum wage per hour of work. In some states, the minimum wage may be higher than the federal minimum wage. You should consult with a lawyer in your state to determine the state minimum wage. If the state minimum wage is lower than the federal minimum wage, the company must still follow the federal minimum wage.