How much money can one expect to make with renting real estate?

I've been trying to find out online, but with not much luck.
For example, if you buy a house for let's say $200,000, and you rent it out to people, how much does it cost to maintain per month / per year? How long before the renters pay it off for you? And how much money can you expect to make per month / per year, once it is payed off?
Or perhaps an apartment is better to rent out? How much can one expect with that?
I'd love some of your feedback on this. Please add details and examples of costs, profits, etc.

Read more: How much money can one expect to make with renting real estate?