Uber as an app, a service, an install [View all]

So I have my new Android and want to install Uber. I have never used Uber, I thought you just install the app and you're good.

But I see negative feedback about being over charged, like 3 times the quoted price. How does one avoid this? Not that I need a ride from Uber, I hope I never do, but you know things can happen - accidents, breakdowns, theft.

I don't dismiss the negative as baseless. There are other ride share apps that partner with Uber - for people without internet or phones, for example - that also charge an arm and a leg. What's going on here?