That’s down to your financial circumstances. An independent mortgage advisor can help you decide what size share of the property is right for you, along with completing a financial assessment that has to be approved. With shared ownership you are buying a percentage share between 25% and 75% (but could be as low as 10%) of the home’s full market value. You enter into a lease agreement with the landlord from who you are buying from (usually a housing association) and agree to pay rent to the landlord on the remaining share you don't buy. Over time, you can usually staircase (buy more shares of the property) all the way up to 100%, if and when you want to.