As part of Home Depot’s Labor Day Sale, this Ryobi 2.0Ah battery is free with a number of different power tools. You can choose to bundle it with a charger, ratchet or screwdriver kits, or other tools, which start as low as $40. The battery works with the Ryobi USB Lithium system and can also charge mobile devices, with a built-in LED fuel gauge to track remaining power. Shipping is free and the deal ends on September 9. Shop Now at Home Depot