Football fans are being warned about fake World Cup kits being sold in Gloucestershire.
Trading standards officers in the county said they had received a number of complaints about fake merchandise and had seized several shirts.
They are now investigating who is making and distributing it.
Eddie Coventry, of Gloucestershire trading standards, said: "It might look like a bargain, but it's not worth the risk."
Mr Coventry said people should be wary of bargain online suppliers unless they have dealt with them previously and know they are trustworthy.
"Counterfeiters always see major sporting tournaments like the World Cup as an opportunity to sell large amounts of fake goods," he said.
"These are often cheaper than official merchandise, but they are usually much worse quality and by buying these products online, you could be putting yourself at risk.
"Criminals can make use of your debit and credit card details that you provide when buying from bogus web retailers."
In one case an online retailer offered shirts at £17.99 instead of the typical price of about £35, Mr Coventry said.
The retailer did not make reference to cancellation rights, did not give an address and, on a web domain registration, had identified himself as a non-trader.
Gloucestershire Councillor Will Windsor-Clive said: "There is understandably huge excitement around the World Cup and people will want to show their support for their country.
"I'm sure that football shirts and other merchandise will be flying off the shelves, but it's important to be vigilant."