Rechargeable Batteries (Eneloop)

Americans throw away 3 billion batteries per year, leaking heavy metals into soil and groundwater. Panasonic's Eneloop batteries can be recharged 2,100 times. A 4-pack with charger costs $18-25 and replaces 8,400 disposable batteries over its lifetime. At $0.50-1.00 per disposable AA, that's $4,200-8,400 in savings. Eneloops hold 70% of their charge after 10 years of storage — a feat no disposable can match. They're pre-charged with solar energy at the factory. The technology has been around since 2005, and there's still no better rechargeable on the market.