Gooloo via Amazon offers the Gooloo Portable 600-amp Peak 15,000mAh Car Jump Starter/Battery Charger, model no. GP37, for $99.99. Coupon code "DBBL6KQV" cuts that to $63.99. With free shipping, that's $436 off list and an extremely low price for such a charger. It features dual USB ports and safety protection.