Price controls
The problem with the approach is that according to the Law of Supply and Demand, the price of a good or service depends on its supply compared with the demand for it. If the price is fixed below the price the market would normally ask, the demand will increase - the product is "cheaper" than it should be. In general, the supply is fixed- at some point it is not possible to increase the production, and the supply. In the long term, it will therefore not be possible to meet the demand, and there will be a shortage.