Rechargeable batteries have been around for a while but now you can recharge them with your computer.  This makes is convenient and easy to put some life back in your batteries.  They are 20 bucks to buy a pair but if you think that you get about 500 charges before it starts to lose its effective charge quickly – this would save umm, about $80 in the long run.

GET IT HERE:
USBCELL AA Rechargable Battery – 2 Cell Pack – MXAA02