Efluky by Amazon offers its Efluky 20-volt 2.0Ah Lithium-Ion Cordless Tool Battery 2-Pack, model no. efl-9687, for $35.99. Coupon code "AGSUFEZK" drops it to $30.59. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $5.55.) That's tied with our mention from three weeks ago and the lowest total price we could find today by $20. They're compatible with Black & Decker cordless tools.