Cash crops are agriculturally grown plants whose function is to generate a return on investment. Subsistence-crops, unlike cash crops, are grown to meet the needs of those producing them, rather than for sale as commodities. Virtually all crops grown in developed countries are sold for profit, and crops such as coffee, tea and tobacco are well known examples of cash crops. Cash crop exports however, from developing countries, have been blamed for a variety of serious economic problems. Because cash crops are exported internationally at prices unaffordable to the local populous, locals are prevented from purchasing the crops themselves or using the farmland to subsistence farm, resulting in economic stagnation and even food shortages.