Buy Backup Cell Batteries

Few weeks ago, I noticed my cell battery was acting up. I tried to look for some cell batteries online but they're kind of expensive. I decided to wait until they're on sale. Fortunately, my friend from California told me to check The Source. I'm currently browsing their wide selection of cell phone batteries online. I'm planning to buy a back up battery. She did mention to always make sure I have a backup battery when it comes to my cell phone.