First, let’s discuss post-implementation cost. As you now know, an affiliate only gets paid when a conversion occurs, e.g. earning a commission on a sale on an e-commerce website. Influencers, however, are usually paid a flat monthly fee to promote the brand by using free merchandise from the advertiser, with no guarantees of performance. This can be a huge risk for advertisers who may see no return on their influencer investment, whereas performance-based affiliate marketing is considered to be very low-risk.
If you have a propensity for writing and you can slay with your prose, consider writing an ebook. While the market has certainly become saturated as of late, books that help teach people about a technical topic still sell extremely well. This is a great source of passive income but does require a large amount of effort at the outset before any money is generated.
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.