That link to LightsCastle has been the cheapest I know of and I've had some good dealings with LightsCastle recently. There is a thread on the Lightscastle HD2010 too. It has been found that the FandyFire's seem to be a little better build than the other *fire brands. It's at least the same. I bought the Ultrafire HD2010 from T-Mart because they gave a discount and it was shipped from a US Warehouse. It's a very good build quality. Much better than the typical cheaper $10 to $15 budget lights. Like I've said, mine is dead and I don't know why. I don't like the direct drive on high driver anyway, so I am planning to mod it with a regulated driver and a U3 emitter (apparently my emitter is dead). The only issue I am aware of with these HD2010's is the potential for the metal reflector base to short the wires at the LED. You just need to add an insulator there. Apparently many users have done nothing and not had an issue.
-Garry