Police in Cardiff are warning of an apparent scam that has taken place in the Roath and Cathays area.
On Friday, February 3 South Wales Police received a report from a student that he had been approached by two men in Maindy Road offering to sell speakers at a reduced price.
He handed over his money but the items turned out to be faulty.
Since then student liaison officer Pc Tim Davies had become aware of two further similar incidents also involving students.
He said: "The student was approached by two men in a van on Tuesday, January 31 stating they had spare speakers to sell.
"They claimed they were top quality and allowed him to listen. He then paid £270 for the speakers but when he got home he found they were of very poor quality.
"We would always advise buying electrical items from a reputable supplier - if the offer seems too good to be true,! then it probably is."