Northern Tool takes up to 70% off a range of tools, storage items, heaters, and accessories during its Year-End Inventory Reduction Sale. Plus, bag a $10 Northern Tool Gift Card with orders of $100 or more, a $25 Northern Tool Gift Card with orders or $250 or more, a $50 Northern Tool Gift Card with orders of $500 or more, or a $100 Northern Tool Gift Card with orders of $1,000 or more, via coupon code "262493". Opt for in-store pickup where available to avoid shipping costs, which start at $5.99. (Free shipping is available for select items.) A couple of best bets, with price compares factoring value of gift card:
Batteryminder Plus Charger/Maintainer / Desulfator for $19.99 (pictured, $17 low)
You very likely are putting your laptop battery into an early grave.