Intro: Cheap Lithium Battery Solution
Basically through building my own custom homemade wrist phone charger, I discovered a alternative to having a lithium battery thats cheap but also efficient. Its a Playstation 3 Lithium-Ion battery with the JST (Japanese Solderless Terminal) cut off so you can easily use it with any project. Its easy to use and gives 1800 mAH of battery power for around $4. They can be found at local locations like walmart as well.
Link to a PS3 Battery-