Neo-Marxists believe an economic system brings about wealthy owners and poor workers. Also, according to them some social institutions like schools, churches, and prisons were created in order to maintain the division that exists between the rich and the poor.
They also believe that social programs such as food stamps and holiday pay are concessions made to the working class to stop them from rebelling.
This change in price means that there is a shortage of lettuce and the price of tacos will increase. That if tacos are made with lettuce and everything else remains constant (ceteris paribus).