Property

Building your first-home deposit

Quidsmith Guides · Updated 2026-07-03 · 6 min read

Game context, not financial advice. This article explains how things work inside Quidsmith, a personal-finance simulation game. The numbers are illustrative and the model is simplified for play. It is not personal financial advice. For decisions about your own money, speak to a regulated adviser.

You start Quidsmith renting, and one of the first big milestones is buying a home. The gate is the deposit. Unlike your retirement pot, a deposit has a deadline, and that single fact should shape both how you build it and where you keep it.

How much you need

The starter flat costs £250,000, and a mortgage typically wants a deposit of around 10%, so roughly £25,000, plus stamp duty on top. That is the target. A bigger deposit shrinks the loan and the interest you pay on it, but reaching the minimum is what unlocks ownership, and every year you own instead of rent is money that stops leaking out as rent.

Let the Lifetime ISA do the heavy lifting

The single best deposit tool in the game is the Lifetime ISA. It adds a 25% bonus to everything you pay in, up to £1,000 a year, and the £250,000 flat sits comfortably under its £450,000 first-home cap. That bonus is a straight discount on your deposit.

Five years of paying in £4,000 a year. In an ordinary account it is £20,000; in a LISA the government bonus turns the same £20,000 of your own money into around £25,000, close to the whole deposit on the flat.

The catch is the LISA's lock. It is penalty-free for a first home or from age 60, but pull it out for anything else and a 25% charge claws back more than the bonus gave. For deposit money you are committed to spending on a first home, that lock is no obstacle. It only bites if your plans change.

A deposit is not a place for the ETF

Here is where a deposit differs from long-term investing. Because you plan to spend it soon, a bad market year at the wrong moment can wreck it, and you do not have decades to recover. The Global ETF that is perfect for a 40-year pension is dangerous for a deposit you need in three years.

The same £25,000 held safely versus invested the year before you buy. The upside is nice; the downside can put the home out of reach. A deposit with a near deadline belongs somewhere stable.

So the sensible homes for deposit money are the ones that hold their value: a Cash ISA or easy access savings for the bulk, with the LISA capturing the bonus on up to £4,000 a year. If your purchase is many years away, a little ETF exposure can make sense early on, shifting to cash as the deadline nears.

In the game

Open a LISA early, before 40, even with a token amount, so the option is alive when you need it. Feed it up to £4,000 a year for the bonus, top up the rest of the deposit in cash-like wrappers, and keep it separate from your emergency fund, which still has to cover shocks while you save. Reach the deposit, buy the flat, and you swap rent for an asset that compounds for the rest of the run. The case for that swap is in rent versus buy.