MoneySavingExpert was established in 2003 by personal finance journalist Martin Lewis.
Lewis will become an employee of the MoneySupermarket.com group once the deal is completed and will be editor-in-chief of MoneySavingExpert.
A £35m upfront cash payment will be made as part of the deal alongside approximately 22.1m MoneySupermarket.com shares. There is also a deferred consideration of up to £27m subject to performance.
The deal is set to be concluded in September or October and is subject to MoneySupermarket.com shareholder approval.
The MoneySavingExpert website offers free online services and editorial on credit cards and loans, shopping, deals and vouchers, utilities and phones, banking and saving, travel and motoring, insurance, mortgages and homes, and income and family.
MoneySupermarket is a price comparison website which covers the likes of mortgages, credit cards and loans.
Lewis says the deal will see MoneySavingExpert retain its editorial independence. Lewis will be giving £10m to charity including £1m to Citizens Advice
MoneySupermarket Group chief executive Peter Plumb, says: “We’ve worked closely together for years with the common goal of helping customers save money. By joining forces we can get more people to save more money.
“We’ll help MoneySavingExpert.com reach a wider audience and MoneySavingExpert.com will broaden the range of advice and tools we offer, encouraging even more people to take action, tap into the benefits of the internet to find a better deal and make the most of their money.”