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charging (a fee); billing; charge
paying for virtual goods or premium features (in a video game, on a social networking service, etc.); microtransaction
ついついゲームで課金してしまう。
I end up making in-app purchases.
課金しなくても楽しめるゲームがいい。
I like games enjoyable without paying.
課金の上限を設定した。
I set a limit on in-app purchases.