There appear to be a spate of this particular scam going on especially in Wales. A man in a white van will drive along side pedestrians and ask if they want to buy a mattress. They will show you a nice mattress and if you decide to buy they will give you a 'new' one that is all wrapped up. This will most probably be either dirty, used or not conform to safety standards.
I know you're probably thinking 'what kind of idiot falls for these things?' but there must be some idiots because the scammers wouldn't bother doing it so it's best to arm ourselves with knowledge about these things and pass the word around. Cheers