Has anyone ever bought one of those cheap breathalysers on eBay before? Do any of them actually work correctly? If you did buy one that worked, how much did it cost and can you provide a link? Here's a link to a bunch of them: http://electronics.shop.ebay.com/Breathalyzers-/58037/i.html?_catref=1&_fln=1&_trksid=p3286.c0.m282 Thanks.