A shave brush is one of the primary tools used to make your lather and apply it to your face (or other parts of your body). They come in an array of varieties but the most common ones have either badger, boar, horse, or synthetic and sometimes a combination of any of these. Prices vary depending on many things including the length, knot density, type of hair, loft, and handles. The bottom end synthetic brushes can be around the $10 or less whereas the top of the line silver tip badger hair can be as much as $400+.