Whether it’s an important consumer application, a specialist app to solve a particular niche problem, or even a time-wasting game you can play on your phone, you can create a massively successful business if you build software that helps people. (Look at the rise of Slack—the team communication software that went from side project to billion-dollar company in just 2 years.)
I would not bother boosting Facebook posts. That does not perform well. The best strategy is to create a custom audience of your visitors and email list. You may want to use that to create a look-alike audience as well. Then have a sales funnel and email campaign. For instance, you are going to get much better conversion rates from a warm lead who has already received some great free content.
ClickBank represents primarily digital or downloadable products. These typically have high-percentage payouts to affiliates. The commissions average around 50%. You do need to be careful and closely vet all products. There are some great products, some good products, and many crap products. You need to be sure the product and the promotional methods are appropriate for your audience. But ..