Money Saving Expert Martin Lewis has said that millions of Brits are missing out on making an extra £1,000 each year.Speaking on Good Morning Britain, he said: "If you're aged between 18 and 40 you're able to open a lifetime ISA."So you can put £4000 per year in and the state will add £1000 on top of that and you can do that each year."To buy a house the house has to cost less than £450,000 and you'll have to have had the account for more than a year before you can use it."He continued: "The