Andy Burnham has promised a series of measures to tackle the cost of living, including a ban on fake discounts and making it easier for people to escape unwanted subscriptions.

The crackdown on “rip-off” business practices is expected to benefit consumers to the tune of £400m a year and will be the first in a range of “everyday fixes” to be implemented in the coming months.

Writing for the Guardian, the prime minister said his government would step in wherever it could as he sought to put the cost of living at the heart of his premiership.

“We won’t be able to solve every frustration overnight,” he wrote. “But where the government can save people money, remove an unnecessary obstacle or simply make something work better, we should and we will.”

The government will ban misleading pricing practices that retailers use to make discounts appear better than they really are, including fake “was” prices, invented reductions and misleading recommended retail prices.

Ministers will consult in the autumn on the precise practices covered and how the ban will work, before introducing the changes through secondary legislation.

Downing Street hopes the measures can be implemented as soon as possible and does not expect a lengthy parliamentary process.

The changes are intended to stop retailers inflating the price of an item before cutting it to give shoppers the false impression they are receiving a bigger discount.

Burnham wrote: “If something is advertised as half price, it should actually be half price. We’ll make sure that when families snatch a deal, they can be confident they’re actually saving. That’s the least they deserve when budgets are so tight.”

The government is also speeding up new protections against subscription traps, bringing forward their introduction from next spring to January. The rules will force businesses to provide clearer information when people sign up, regularly remind customers about their subscriptions and make it easier for them to cancel. Customers will also be given a 14-day cooling-off period after a trial ends or a long-term contract renews.

The average person has about three subscriptions and spends about £500 a year on them, according to government figures. There are about 155m active subscriptions across the UK, and about £1.6bn a year is spent on unwanted ones.

Ministers estimate consumers will save an average of £14 a month for each unwanted subscription they are able to leave early.

“Too many companies want you to sign up in seconds but then make it feel impossible to leave. It’s exhausting,” Burnham wrote.

The challenge for the prime minister will be whether smaller consumer-oriented interventions can provide savings households notice when many are still under pressure.

The two measures will be followed by more over the coming months as he attempts to show voters his government can make a noticeable difference to household finances.

Burnham also promised “bigger plans to make life easier and fairer for people over the longer term”, but Downing Street has yet to set out what those will include.

Burnham wrote: “As far as I’m concerned, whatever the size, big or small, if it’s a problem for you, it’s a problem for us. That’s why I’ve made it clear from day one that creating room to breathe is my number one priority, and the whole of government is united on that.

“Every single unexpected payment, rip-off or hidden catch chips away at hope. That might sound dramatic – but it’s true. Every single one is another message that thiscountry is built to catch people out rather than help them get on.”

Citizens Advice welcomed the changes but said they “can’t be the end of the story”.

The announcement comes as Burnham prepares to spend the rest of his summer travelling around Britain in an attempt to reconnect the government with voters, particularly in areas where Labour has lost support.

“I’ll be asking people what action they want to see on the cost of living,” Burnham wrote. “Because if we want to find the problems that make everyday life harder, we need to listen to the people dealing with them.”

Downing Street has not said whether what Burnham hears on the tour will shape the next round of “everyday fixes”.