A best bet is the
Britax Marathon Convertible Car Seat in Sutton (pictured), model no. E9L06G6, for $179.95 before the coupon, $134.96 after. With free shipping, that's the lowest total price we could find by $55. (It's also the best deal we've seen on this car seat in any color since December.) Features include a 5-point harness, multi-position reclining seat, and more.