A Lifetime ISA lets you save up to £4,000 a year and gets you a 25% government bonus, worth up to £1,000 annually.
You can open one between ages 18 and 39, contribute until 50, and use it tax-free for a first home (up to £450,000) or from age 60 in retirement.
Withdraw for any other reason and you pay a 25% penalty, which actually leaves you worse off than your original contribution.
A LISA is the exception to the multi-ISA rule: you can only subscribe to one LISA per tax year, even after April 2024.
