I can only answer for Toronto, Canada but the answer was nothing. Uber has a deal with one of the insurance companies up here so you’re covered at no extra charge. (Intact / Belair Direct).

Uber pays them directly for a big commercial contract to cover you when you’re driving for Uber.

Edit: added "for Uber" on the last sentence

My prior comment may be dated, or regionally-contextual. I assume then you have a personal policy, that covers when you are driving just you, and Uber's takes over when you have rideshare passengers. When I was looking for personal auto policies recently, I recall being asked (in the US) if you plan to do any rideshare driving.

Yes my personal auto policy explicitly covers Uber. I did need to inform them, but my premiums did not change.

"ridesharing drivers operating on the Uber platform in Ontario can now be covered, at no extra cost. All you have to do is call us in order to update your personal auto policy." -- https://www.belairdirect.com/en/partnerships/uber.html

I go thru Geico in CA and commercial ins is affordable. I forget the exact Amy but I'm happy