The drop shipping "gadget" sites like that one, Focalprice, and Dealextreme, often sell unreliable and under-spec lasers. If it seems too good to be true then it probably is.
A good rule of thumb is, if the lasers is and cheaper than about 50 cents per mW, then you shouldn't expect the laser to be up to spec and stable. You get what you pay for. Expect to pay at least a buck per mW for a quality laser, and be sure that it's made by a reputable manufacturer too.
Check out Rayfoss. They have a pretty good rep around here and pretty good prices to boot.