Say hello to your basic four inch foam yoga block ($12). This is the block you'll see most often at yoga studios. It's used in poses when you can't quite reach the floor with your hands; it essentially raises the floor to ensure you maintain correct alignment. It's also a great prop to sit on for meditation, or used in conjunction with bolsters or blankets for restorative poses. This block is one of the most versatile, so it's a great investment if you're new to the yoga prop scene.