Hundreds of thousands of English patients are missing out on cheaper NHS prescriptions, new analysis suggests.
More than 800,000 people would have been better off if they had purchased a prescription prepayment certificate (PPC), according to MoneySavingExpert.com.
The certificates enable patients to make a one-off payment and then get as many prescriptions as they need for the period covered.
The current cost for a PPC is £104 for 12 months, or £29.10 for three months.
MoneySavingExpert said that in the 2016/17 financial year prescription items cost £8.40, so anybody paying for 13 or more prescription items could have saved at least £5.20 by buying a PPC.
The consumer website sent a Freedom of Information request to NHS Business Services Authority to discover how many patients purchased at least 13 prescriptions last year.
It found that 825,677 people in England paid for 13 or more prescription items in the 2016/17 financial year.
The data showed that on average, these patients paid for 18 prescriptions each, and could have saved £47.20, MoneySavingExpert said.
Steve Nowottny, news and features editor at MoneySavingExpert.com, said: "These stats show that a huge number of patients are paying more than they need to for medicine prescribed on the NHS - and in many cases could save almost £50 over the course of a year.
"If you're going to need 13 or more items on prescription in the course of a year and you don't qualify for free prescriptions, the season ticket is certainly worth it.
"And while of course not everyone will know from the outset how many prescriptions they'll need, it's clear many are missing out on savings.
"To be fair, many pharmacists and GPs do tell patients they can save using this scheme, but it's clear there's still a lack of awareness.
"The NHS should do whatever it can to publicise this scheme to patients who can use it to pay less."