Suppose the price of a bottle of water is $5.

Use the black line (plus symbol) to draw a price line at $5. Next use the grey point (star symbol) to indicate how many bottles of water Antonio will buy at that price. Finally, use the green point (triangle symbol) to shade the area that represents Antonio's consumer surplus from his purchases.

In this case, Antonio receivesin consumer surplus from his water purchase.

If the price falls to $2, Antonio now buysbottles of water. This his consumer surplus to.