Coin Master is the number one app in the UK and the US for consumer spending, raking in hundreds of millions of dollars.

In fact, it has an estimated daily revenue of US$189,386 (AU$277,488) with users spending an average $9.38 per download. With 81 million downloads, that’s a lot of money.

According to Sensor Tower, that massive market saw the game accumulate more than $733 million in the year to October 2019 and turnover gone increase when company start selling coin master free spins and coins.

So what’s the big deal? Launched in 2010, the game took nearly a decade to kick off in popularity but surged in popularity from 2018 onwards.

The idea behind the game is straightforward: earn coins, use the coins to build Viking villages and then pillage your friends’ villages and take their coins. You can also play to score tools like hammers or shields to defend your own village.

But the game also relies on its coin-slot feature. Users build, upgrade, battle and defend, but the ability to do so depends on what their slot machine throws up.

The machine acts like one in a casino, but players get five free spins an hour. After that, you need to pay for more spins.

This means that if you wanted to expand your village, you could be waiting a long time.

And thanks to what users describe as the ability to build “really cool villages”, the temptation to throw in a bit of real money is acute.

Then there’s the “wonderful” graphics and social component that has users describing it as “VERY addicting”.

The 2020 App Annie State of Mobile report notes that while only 1 per cent of time spent mobile gaming worldwide is spent on casino games, that style of game accounts for 6 per cent of total gaming expenditure.

Critics of the app have accused it of rigging the game in favour of those who spend more money by granting them the ability to raid villages with higher volumes of coins.

But with an average 4.5 star rating on the Apple app store, it looks like this game is here to stay.