This game is free to download but has lots of in-app purchases.
Tips
usage
Two distinct senses: (1) gaming/app - the iOS/Google Play 'in-app purchase' (IAP) is universally 内购 in Chinese app stores; (2) corporate - staff buying their own company's products at a discount.
memory
内 (inside) + 购 (buy). Whether 'inside the app' or 'inside the company', the structure is the same.