Perfect for the trunk: the EZYFlare Roadside Flare is only $4.97 (free in-store pickup) at Sears. The LED flare is visible up to 8,000 feet away, and can be used on boats, cars, etc.
A quick jog over to Amazon shows that this same flare is selling for $14 there. Not sure how long this sale price will last, but it's a great pickup.
