Pirate leggings (Beige, Red, Blue, and Brown) can be purchased from the store on Mos Le'Harmless after completing the Cabin fever quest. Meanwhile, Pirate leggings in purple (12k), grey (17k) and orange (11.7k) can be only obtained by looting pirate impling / trading among player / G.E. (Price based on G.E 8 August 2008). However they offer no bonuses.