There are a number of different business models and app monetization strategies used by these companies to generate revenue. - Online survey companies sell the data they collect to third parties seeking to improve their products and services. - Many gig economy apps take a percentage of revenue from each transaction. - Cash-back shopping apps like Rakuten are among the highest paying apps for a reason: they earn a solid commission for sending you to retailers’ sites, which they then share with you. Apps that give you money are always getting something in return — whether that's your data, your feedback, your business or something else. Keep that in mind when picking which ones to use and make sure you're comfortable with the tradeoff.