Appgyver's app builder interface has always been one of the better ones out there, imo. They've now released the latest version of their Composer builder which aims to make building enterprise apps a cinch. Haven't tried this yet myself, but the beta seems like it offers a good chance to give this a spin.

so expensive

Appgyver is absolutely the worst of all the app builders. It will waste your time and frustrate you to no end. Every single task is so slow and it makes what could be done with a couple lines of code the most complicated task. It hides the code from you and does not give you a clue as to what is happening. The user interface for selecting bindings shrinks down to almost nothing and forces you to scroll through a list with only an inch of the visible selectable window, while above that is an entire page of empty space. Everything about the user-interface seems like it was built by an idiot. It is the most frustrating thing in the world. Horrible product and I would not recommend it to anybody. I ended up coding a react native app from scratch and it was easier for me to learn react with hardly any knowledge of javascript than it was to try to get Appgyver to do the simplest things. A complete waste of time.