Walmart offers the Stanley FatMax 8-amp Battery Charger bundled with an Extension Cord for $24.30. Opt for in-store pickup to dodge the $5.99 shipping fee. That's a buck under our January mention, a savings of $9, and best deal we could find. It connects with battery clamps, battery ring terminals, or a 12-volt DC plug and features reverse polarity lights that warn against an improper connection.
Vinegar is arguably the most versatile product in your house. If you aren't using it for all of these purposes, you're probably wasting money.