newegg offers the Timbuk2 Crater 13" Laptop Sleeve for MacBook Air in Black/Gunmetal, model no. 393-13N-6023, for $19.99. Coupon code "1105GAMES1" cuts it to $9.99. With free shipping, that's the lowest total price we could find by $19. This sleeve features crater holes to purportedly cool your MacBook twice as fast and high density foam for protection. Deal ends November 11.