Rechargeable Batteries (Eneloop)

Americans throw away 3 billion batteries per year, leaking heavy metals into soil and groundwater. Eneloops can be recharged 2,100 times and hold 70% of their charge after 10 years of storage—a feat no disposable can match. A 4-pack with charger costs only $18–25, while disposable AAs run $0.50–1.00 each. They're pre-charged with solar energy at the factory, and since 2005, no better rechargeable has emerged.