How much does a recording studio earn?

That's a difficult question to answer ;)

It's similar to asking "How much does an artist earn?". Since the answer can vary greatly I can only give you a range.

Recording studiOS can earn anything from negative money per hour (ie: they're LOSING money by running a recording studio), anywhere to $300 or more per hour (depending on factors such as cost of the studio engineer and more).

To price out a recording studio, you should look at your budget first and get testimonials of previous clients.