£5bn 'wasted' on phone tariffs
In a study of 2,034 people, nearly half (47%) were unaware of their data allowance, and number of free minutes and texts on their contract.
The research, released by Carphone Warehouse, revealed there are now more than seven million mobile phone deals on offer in the UK.
The figure has been fuelled by the recent rise in smartphones with internet access - which has added an additional layer of complexity to an already baffling arena, pollsters said.
Andrew Harrison, Carphone Warehouse chief executive, said: "When the UK is facing one of the hardest financial times in living memory, it seems crazy that £5 billion is being wasted on phone bills.
"At Carphone Warehouse, we want people to enjoy their smartphone without costing them an arm and a leg. That's why we're urging people to let us help them. We'll compare every network and phone combination and give independent advice on which deal is best.
"The cost of data charges is a growing issue and this is only going to increase as more people convert to smartphones."
Lack of awareness was cited as a problem among phone users - people did not realise that video calling a friend through the Skype app (51%), logging into Facebook through an app (43%) and having a Twitter app stored on the phone though not in use (81%) all contribute towards their data allowance.
Ambiguity also existed around the terminology used to describe data with customers generally unsure what one 'megabyte' meant when put into the context of the number of songs that can be downloaded (79%), the number of emails that can be downloaded, read and sent (83%) and the number of minutes that can be watched on YouTube (87%).