The 'free trial' offers claim to have visible results within days
Consumers in South Lanarkshire have been conned out of cash after signing up to a "free trial" of teeth whitening products.
Trading Standards officers discovered the scam on a number of US-based websites.
Customers were asked for credit card details to cover a handling fee of about $2, but were then subsequently charged about £55 a month.
People have been warned to read the small print on all internet offers.
The "free trial" scams often claim visible results "within days".
However, what many consumers do not realise is they are actually entering into a 'Lifetime Membership Program' or an 'Elite Customer Club' that can be very difficult to cancel.
One individual who contacted the Trading Standards team at South Lanarkshire Council had multiple transactions on her statement from different companies. The only way to stop the payments was to cancel the credit card.
Trading Standards manager Peter Sherry said: "When a consumer enters into an online contract with a business within the UK, or even the EU, they have certain rights.
"The business has an obligation under both Distance Selling legislation and Consumer Protection legislation to provide all important information and cannot hide material information to the contract.
"Consumers would also have a right of withdrawal, also known as a "cooling off" period."
He added: "Contracts made with American companies, however, are not regulated in the same way.
"Although most of the teeth whitening 'free trials' claim that the consumer can cancel at any time, the reality seems to be that the cancellation process is made too difficult.
"It is important for consumers to be very aware of what they are agreeing to when purchasing goods or handing over their credit card details to a business from outside the UK."