the main reason to have spare batteries for me at least is to keep the spare batteries charged up and ready to roll. But yes this does require a specific batter

the main reason to have spare batteries for me at least is to keep the spare batteries charged up and ready to roll. But yes this does require a specific battery charger. when i had my HTC Thunderbolt, i got a package deal with 2 batteries and a charger ( that also provided a USB port ) for < $20. I haven't looked for my S3 yet...