Fertilizers are effective for encouraging plant growth and are good for keeping ground soil healthy. The cost of fertilizer can depend on your purpose for it. If you would like to apply fertilizer to your lawn and garden a generic brand from a discount, hardware or home and garden store will be sufficient. The average cost for this sort of fertilizer is between $20 and $30. An alternative to store-bought fertilizers are organic ones such as manure, compost, or seaweed which is often available free of charge.