Government system of allowing only small amounts of items to be bought

Rationing

Explanation:

Rationing is a method that is used to distribute a resource in a period of extreme scarcity. Example of rationing would be what the soviet union did during the communism era.

At that time, the lack of production in that country make foods became extremely hard to get. So the government only allow the citizens to obtain small amount of food in order to ensure that all citizens can have something to eat.