Amazon offers its Prime members the Duracell Mini AA Battery Charger Kit for $5.20. Clip the $1.50 off coupon beneath the price to drop it to $3.70. With free shipping, that's the lowest total price we could find by $6. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $5.17.) The kit includes one mini charger and two AA batteries.

Amazon Prime membership is $79 per year; however, Prime is free for college students for six months, and free for parents and caregivers for three months.