Black Friday Deal. Prime members only. Amazon with GOOLOO has the GOOLOO GT4000 4000A peak 100W Car Jump Starter for $99 with free shipping. Here's a comprehensive review.

Can jump batteries as cold as -40℉ (pre-heating function), 3.2-inch LED screen,  IP65 water-resistant, 26800mAh capacity, 400 Lumen LED. Includes jumper clamps and several charging cables.