I'll need some more information before I can give you an answer.
Does your son live with you? How old is he?
Is there anyone else in your household?
Do you own a home, or do you rent?
Do you pay more than half the cost of the household?
These are all questions that you will have to answer to file a tax return.
Assuming you are HOH with one dependent child:
You may be eligible for Additional Child Tax Credit if your son is under 13.
This could get complicated, I'm afraid. You mentioned a room mate, so there is someone else living in the household. this could affect both your HOH status and EIC eligibility. If your room mate also files a return from the same address, there may be questions raised about who is eligible to claim HOH or the EIC. this will depend on inter-related factors such as relative income, amount of household expenses paid, relationships, etc. Be sure you read the instructions carefully before filing your return.
Other than that, if you qualify, the numbers sent by LEV will give you an idea of what your federal tax will be. Also look at things like retirement plan contributions and higher education expenses. As you can see, there's no general answer to how much tax you will have; everyone's situation is different.
Yes, as I wrote earlier, that's for federal tax. Maryland has an EIC of %0% of federal EIC, up to the amount of tax. Expect a MD tax f about $375, offset by EIC, for a net tax of zero.
The state of MD provides EIC at 50% of the federal rate.
Lev's answer was the amount of tax on your income, and the EIC amount would reduce the tax by that amount. If the EIC exceeds the tax, the balance is refunded; sort of a negative income tax. Maryland does not rfund the excess EIC.