How much you will earn that is depends on you. What are your skills, what is your educational qualification , how much experienced you are. Also depends on your efficiency , communication ability, English skill, resume service etc. And depends on job type some job have very demand some are less.
Now come to the point. how much you can earn per month ? Answer is yes you can even easily earn $500 to $1000/month but you have to be very efficient, qualified and skilled. Any how you can at least earn $500 /month by doing data entry easy job primarily. If you are a new freelancer, you have to show your quality . Otherwise its very difficult to get a good job. Gradual you will get paid more according to your experience. You have to be very patience for the first job and should handle the job carefully. Never be frustrated. Be patience Just start the process now . all this are described in my site gradually.
For a better earning my suggestion is to try to learn a something very well by attending a course or from internet. If you have no skill then first you can start by data entry and try learn something professional like programming, graphics design, web design etc.