This is completely up to you. We have had apps ranging from "instagram for food," to marketplaces, to membership subscription apps, to a plethora of dating apps. It really is up to your creativity as a maker, truly. We have built this so that if you can design it, it can be published, made functional and with a database. Not creative but still want an app? No worries, we have 1:1 build sessions to show you how it's done. Check out some of our example apps here.
We have built our platform with the non technical maker's (no coder) journey in mind. When you have a tech team of your own or just want to push the pause button, no worries. You can walk away with your source code at any time. Just go to publish and then hit the export source code button.
Simply put, it costs bandwidth to run builds through the app store and to publish source code. In addition, this can be looked at as a built-in quality control. We want makers to think about when they publish or export and not press publish a million times (this has happened when we didn't charge). So, in a manner of speaking the $99 fee is our first line of defense from publishing garbage and ruining existing relationships (again, this has happened).