Martin Lewis has warned people about big changes coming to overdrafts - with daily charges being abolished from April 2020.
Banks are being forced to get rid of unarranged overdraft fees and charge customers interest rates instead.
However, as Lewis pointed out, the standard rate for overdraft interest could be massive.
"The problem with overdrafts is that they're a stealth debt," said the finance journalist.
"You don't apply for them, you just end up in them.
"Back in 2005, banks would charge £35 a pop for going overdrawn. It would be £35 per transaction, i.e if you made seven transactions, you'd be charged seven times."
Lewis also claimed the system has been "designed to entrap customers," but the new laws arriving in spring will prevent banks charging fines like they have in the past.
8pm tonight ITV... my show is on - all about the new virtually standard 40% interest on overdrafts; over doubel a high street credit card, and what you can do to beat it.— Martin Lewis (@MartinSLewis) January 13, 2020
Plus do you know your return rights on goods bought online and instore?
Do watch if you can. #martinlewis
"Last July, the regulator said that from April 2020, banks will no longer be able to charge you a fine for going over your overdraft limit," said Lewis.
"That means that while they can still charge you what it costs them, they won't be able to impose daily penalty charges.
"It took 10 years, but we got a win."
The new laws have led to many leading banks - like HSBC, Nationwide and M&S - simply charging customers a huge 40% interest, and many other major banks expected to do the same in due course.
The bottom line is that being overdrawn will continue to cost you a staggering amount of money moving forwards, so it's important to take steps this year to clear some of that debt.