Northwest-outdoor via eBay offers the Garmin echoMAP 50dv Marine GPS Combo with Transducer, model no. 010-01300-00, for $429.99 with free shipping. That's the lowest total price we could find by $15. It's preloaded with LakeVu HD or BlueChart coastal mapping and features a 5" color display, 10Hz GPS/GLONASS receiver, and two microSD card slots.