Shade sails are similar to canopies, although rather then having posts or frames they are suspended from walls. Shade sails come in retractable designs that offer you control over your sun exposure. Shade sails slope downward to provide water run-off. Their angled design not only provides the perfect sun protection but can also shelter pools and hot tubs from debris and cars from bird assaults. Shade sails come in triangular, square, rectangular and five-, six- or eight-pointed shapes of varied sizes. Many online suppliers will also custom-design a shade sail for you. Small shade sails start as low as $70; while large shade sails can cost $200 online.