I buy all my funky lithium batteries off ebay. They are inexpensive and they work just fine. Mostly from Hong Kong and China sellers, but some USA sellers too.
And none have exploded and burned down my house yet...am not saying it couldn't happen but the batteries work and charge fine and make the flashlight really bright.
Just look on ebay and find the least expensive ones and buy them and they should work. Sure you can pay 5x that amount for a more dependable and safer battery, but that cost/benefit equation is up to you to figure out.
You are playing the Li lottery. Those battery are generally repackaged and refurbished batteries removed from larger packs. You may get a decent battery or you may get one at the end of its life cycle. It really depends on how much you value the dependability of your batteries and the safety of you flashlights. If you use your flashlight for work or something important, don't buy no-name batteries from ebay or dealextreme, etc. Really bad idea.