When you purchase something at the store,you pay what's called the market price.Currently,the market prices of most goods and services don't include a calculation of the products' environmental effects.For example,when you buy paper,the price you pay covers the cost of raw materials,labor,manufacturing,packaging and maybe the fuel to deliver the product to your local paper store.What it doesn't include is the cost of air pollution created during the manufacturing process or of the soil erosion,water pollution,and habitat destruction that deforestation causes.