Home Depot offers the Grape Solar 200-watt Off-Grid Solar Panel Kit, model no. GS-200-KIT, for $429.99 with free shipping. That's the lowest total price we could find by $119, although most retailers charge over $650. It provides up to 600 watt hours or 50 amp hours of power per day and is designed for cabins, RVs, boats and other off-grid uses. Deal ends May 17.