id say as with everything you only get what you pay for, there is a company on ebay selling genuine hairmax laser combs that have been returned to them much cheaper than they retail for.. the cheaper versions could be using red LEDs instead of a laser or budget laser tubes
ref the cost id say even buying one new is very cheap when you think about how long they last & compared to 6 months treatment using a laser helmet at a hair regrowth studio ( ??3000+ )