Adverts for broadband services from BT, Sky and Talk Talk have been criticised by a charity for not making the real costs clear.
Citizens Advice has complained about three ads to the Advertising Standards Authority, saying that promises of free or cut-price broadband deals for a set time are misleading, meaning consumers buy contracts that turn out to be more costly.
The adverts appear to offer deals ranging from free to £4.50 a month, but the actual average price per month during the contracts ranged from £19 to £29. One contract, advertised only as "Free for six months", would have cost £500 over 18 months once installation fees and line rental were factored in.
Gillian Guy, chief executive of Citizens Advice, said: "Attractive offers can lead to bigger costs. People are being lured into costly contracts because additional charges are hidden in the small print.
"Consumers need to see the total cost to make comparisons. The industry needs to improve the way it advertises so consumers are clear about what they are paying for. We hope the ASA will take swift action."