How they do it: A lot of apps in the Apple AppStore are accessible for free but then only allow using limited features or a trial period for the full version. To have access to the full version permamently, the user has to purchase a premium version.
Learn more about Apple iPhone/AppStore →
How they do it: AWS gives away free ”credits” to use their service and set up ones infrastructure on the AWS cloud computers However as soon as the company’s product need grow and exceed the capacity covered by the free credits, it has to pay for the additional use.
Learn more about Amazon Web Services →
How they do it: A basic version with limited hosting space is offered to customers for free. However, customers then have the chance to purchase subscriptions for larger amounts of storage space.
Learn more about Dropbox →
How they do it: Amazon is giving away a free 1-month trial for its premium subscription ”kindleunlimited” which allows the customer unlimited access to media such as e-books, magazines and audio books for a flat fee payable every month. This enables customers to test the service and Amazon to upsell the full subscription to users of the free trial.
Learn more about Amazon Kindle →
How they do it: Much of Skype’s service is free. Skype-to-Skype calls to other users are free of charge, while calls to landline telephones and mobile phones (over traditional telephone networks) are charged via a debit-based user account system called Skype Credit.
Learn more about Skype →