How many lights should I buy?

[Noah001]

I'm a totally newbie and want to buy this light on ebay, please look at the parameters, it suits for small tent which just able to grow two strains? How many lights should I buy? Anyone has bought one like this before?
LED grow light HY-MD-D169-S

 

[Old Scratch]

I haven't used LED. Being that no one else seems to have much to say, see if you can do a search for that exact model and find reviews elsewhere. Personally I don't have too warm and fuzzy of a feeling towards LED. It just seems like it is dumbing the light spectrum down. It seems like a high PAR rating coupled with a broad spectrum of light is the way to go. I base this off of observations of plants under various types of lights as well as those lights vs the sun. It just seems like they appreciate more than simply blue, red and a little white.