Rental Income and Finances

So I talked to my uncle today and he said my grandpa's basement is renting for $800/month and the upstairs for $1100/month. One thing though, I have to take it with a grain of salt because only a month ago he said he didn't know how much it is renting out for. So those might not be the exact numbers. Anyways I will be getting half of the month's rent each month. But the thing is that we pay the utilities, so that will take out a huge chunk in the winter, and we have to pay the property management company around 15-20%, but I am not sure exactly how much we pay the property management company. Anyways even though I get half the months rent each month, I may only get $400 a month. On the other hand, I may get as much as $700 each month. It is kind of up in the air. But I will know as soon as my uncle has paid off the roof, because thats where the rent money for each month is going right now. It should only be 1-3 months until I start getting money. I'd be happy with $400, that would allow me to save a lot of money. I would save around $5000 a year. I'm facing a lot of pressure from my mom right now because she is paying my expenses. I can't wait until I'm a doctor and I don't have to worry about money anymore.