My original battery is getting pretty old and doesn't last very long. Where should I buy a new one? I've seen places selling original stock for $80, but those batteries are the same age as mine (but they have not been used). I have also seen a place that will sell you a "refilled" battery for $100. The most expensive I've seen is a NewerTech (new?) battery for $129. I wanted to post in the marketplace in case someone has one to sell, but I don't have enough posts to post in the Marketplace. WhadYa think?