Also referred as Commission Junction, CJ is a large affiliate network offer affiliate programs for a wide range of popular and well-established organizations. This program acts as the intermediary between the merchants who will provide the products to sell and the affiliates who will do the marketing. This program is very advantageous as it provides very many affiliate programs at the same place.
If you have a good idea for an app, and the skills to create it, then producing your own premium app can be profitable. However, with so many free apps available, it may be hard to convince people to pay. If you want to go down the premium app route, consider having a basic free version to encourage people to download the app in the first place. You can then provide the option of upgrading to a premium plan once users realize how useful the app is.