Renting for profit isn't just a comparison of cash in v. cash out. As indicated, your total mortgage payment is not deductible; only the interest and property taxes are. However, you do get to deduct depreciation, so that must be factored in. If your rental income is more than your rental expenses (as defined by the IRS) for at least 3 years out of a period of 5 consecutive years, you are presumed to be renting your property to make a profit.
To determine if you are renting at Fair Market Value, look at comparable properties, or ask a local real estate agent.
