Knowing how to develop a mobile app is only part of making it successful; it is also essential to monetize the app. However, the most obvious way to make money from an app is not necessarily the most effective. Simply charging users to download an app works in certain circumstances, but 2012 research from Gartner showed that 89 percent of mobile app downloads were free. With so much free content available, it can be hard for users to justify paying to download an app.

That’s why “freemium” apps have become popular. The initial download costs the user nothing and allows access to certain content without having to pay for it. Freemium apps make money by charging subscriptions for a higher tier of service or content, or through in-app purchases for discrete pieces of content. This business model allows users to download and try the app with virtually no risk, while at the same time incentivizing purchases in the long term.

Money Making Apps

The vast majority of apps on Apple’s and Google’s app stores are free to download, with freemium content unlocked once the user has a chance to sample the app. Here are some of the most successful freemium apps in the mobile marketplace.

Candy Crush Saga

Developer: King

While King previously ventured into the mobile games space with Miner Speed, Candy Crush Saga was the company’s first break-out success. It set out to make a game that could stay in the top 10 on Facebook for a week — and King exceeded that goal. In 2013, King reported profit of $567.6 million, up from $7.8 million a year earlier. Candy Crush Saga was a massive overnight success, with more than 93 million people playing the game.

Candy Crush Saga paved the way for King’s IPO and, in 2013, revenue from the game made up around 78 percent of King’s total $1.9 billion revenue.

Pokemon Go

Developer: Niantic

Twelve months before Pokemon Go’s launch, it looked like developer Niantic might not be around much longer. During Google’s 2015 reorganization, it became likely that Niantic might be folded into the tech giant’s Android division or shuttered entirely. But John Hanke, with Google’s permission, sought outside investors for the technology he had pioneered with Niantic’s first game, Ingress. Hanke found a partnership with The Pokemon Company, and Pokemon Go was born.

The augmented reality game broke download records during its first year and became the fastest mobile game to make both $500 million and $1 billion in revenue.

Clash of Clans

Developer: Supercell

Finnish company Supercell got into mobile games with the farming simulator, Hay Day, which enjoyed some success. It was, however, quickly dwarfed by Clash of Clans. Supercell wanted to find a way to bring hardcore strategy gamers from the PC into the mobile market and, in Clash of Clans, it may have managed to do just that. Having generated $892 million in 2013, Clash of Clans became the top-grossing mobile game on iOS and Android in 2014, after months in second place.

Clash Royale

Developer: Supercell

Supercell didn’t rest on its laurels after the success of Clash of Clans. In 2016, the company unveiled the head-to-head game Clash Royale, which became the world’s top-grossing game, with $80 million in revenue in its first month. During the first quarter of 2017, Clash Royale was the second-highest grossing game in the world.

Game of War: Fire Age

Developer: Machine Zone Inc.

Game of War, from Machine Zone Inc., has seen enough success to attract celebrity TV commercial endorsements from Kate Upton and Mariah Carey. In 2016, it was estimated that the average Game of War player spends around $549.69 per year on the game, far more than the average mobile gamer ($86.50) or console gamer ($91.58). This makes Game of War one of the highest-grossing mobile app games in existence.

Gardenscapes

Developer: Playrix Games

Russian developer Playrix has produced three international hit games: Township, Fishdom and Gardenscapes. Township made Playrix No. 2 in Europe’s mobile gaming market, but its third mobile game, Gardenscapes, had around 3.5 million users by 2016. Though Playrix has focused its efforts primarily on creating individual games thus far, the company recognizes that, in order to compete in today’s mobile market, it must work with brand owners and create licensed properties.

Toy Blast

Developer: Peak Games

Peak Games founders Sidar Sahin and Bugra Koc started the Istanbul-based game developer to change the world. They wanted to create a space for tech startup culture in the Middle East, to lead tech innovation in a region primarily focused on physical products. Their flagship game, Toy Blast, has been installed on tens of millions of Android devices and has produced a total estimated revenue around $118 million.

Slotomania

Developer: Playtika Ltd

Competing in the social casino games space, Israeli game developer Playtika made a name for itself with the game Slotomania. Credited as the company that invented the concept of playing virtual casino games with virtual money, Playtika created Slotomania to put that concept into practice for slot machines and, as of 2014, an estimated 5 million people in more than 190 countries were playing it daily.

Roblox

Developer: Roblox

David Baszucki, co-founder of Roblox, doesn’t see Roblox as a game; rather, he sees it as a “human co-experience,” a virtual online playground powered and driven by user-generated content. Roblox is available on mobile devices, but also on console and PC — even virtual reality — and has achieved 48 million active users as of 2017. Because Roblox relies so heavily on user-generated content, the most popular creators in the game are paid by the company, sometimes as much as $140,000 per month.

Episode – Choose Your Story

Developer: Episode Interactive

Episode is an interactive storytelling game aimed squarely at Generation Z. The game features interactive, animated storylines based on TV and movie properties, from Mean Girls to Pretty Little Liars. The Mean Girls episode got an estimated 49.6 million unique viewers, and users have spent more than $35.7 million on the app. They can even submit their own stories — which the game automatically animates — that can be shared or kept to themselves.

Marvel Contest of Champions

Developer: Kabam

In only seven months, Marvel Contest of Champions surpassed $100 million in gross revenue. As Kabam’s fastest-growing game ever, Marvel Contest of Champions has been downloaded more than 40 million times and is the top-grossing app in 106 countries. The game’s success has enabled Kabam to pursue a Chinese launch, as well as cement relationships with studios like Lionsgate, Warner Bros., Disney and Universal.