I see packages on eBay listing a 1800 Lumens CREE XM-L T6 along with an Ultrafire 18650 battery and an external charger with bids starting at under ten dollars and usually going for not much more. Is this a good deal?
no.
Xm-ls are not physically capable of putting out that many lumens, the charger and batteries will be crap to the point of being dangerous, the lights are generally not all that well finished.
Ebay is really tricky to get a good deal on a good light, good cells and good charger. Do not buy into these package deals, do a little reading on the forum, buy a trusted charger, trusted cells, lights you can skrimp on, its a learning curve, bad cells and charger is a much more serious issue.
Very true I purchased an ultrafire 501b package for 12.00 or so. The 3000mah battery it came with was actually 600mah. The light seems painted (the black comes off very easily. It also didn’t put out anywhere close to the 1000 lumens it was advertised as. I have since modded this light into a bright little rocket but I could have gotten one for less already to go. The charger works bt cuts off at 4.15. I bought a pair of Sanyo 2600mah for about 12 on eBay and they actually test almost exactly what they are rated. So take your time look around this forum. The guys here are awesome at pointing you in the right direction.
all these cheap with batteries and chargers are scams
ebay is getting spammed with these for a year or so
Make another ‘recommend me a light’ thread and be specific. you’ll get some good replies 
it is better to purchase the light and battery separately.
you can pick any good XML light that suit your taste aesthetically and budget, then pick a good sanyo or panasonic 18650 and you are good to go. oh, and a dual slot charger like nitecore i2 is sufficient.
i hate those false data