Trading Standards officers at Pembrokeshire County Council are advising consumers to exercise caution following reports of men selling goods from the back of a hired van in Haverfordwest.
The men were selling tools and generators from the van parked at Morrison's supermarket car park on Wednesday (14th June) and are now believed to have moved on to Carmarthenshire.
It has emerged that one elderly consumer paid more than £2,000 for the goods which are believed to be worth considerably less.
Michael Disney, Fair Trading Inspector, said people may feel under pressure to offer some money for the items.
He added: "These goods may not be genuine or safe, and if they are faulty, consumers are unable to get a refund. They might also be vastly overpriced."