Amazon offers Prime members the Panasonic Eneloop Pro AA Rechargeable Batteries 4-Pack and Charger, model no. K-KJ17KHCA4A, for $23.99 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, it adds $6.35.) That's the lowest total price we could find by $5. The batteries can purportedly be recharged up to 500 times.