Just curious.. why are these so cheap?

amazon.com/Panel-Drug-Testing-Cocaine-Marijuana

Are they even worth buying? I need something to see if im clean for a drug test for a job. I know in the description is says its ideal for work place testing.. but how much can I rely on that?
bewpy1 Reviewed by bewpy1 on . Question about buying a drug test online Just curious.. why are these so cheap? amazon.com/Panel-Drug-Testing-Cocaine-Marijuana Are they even worth buying? I need something to see if im clean for a drug test for a job. I know in the description is says its ideal for work place testing.. but how much can I rely on that? Rating: 5