Seriously, you need to sit down and break it all down:
-Property taxes (should be able to look up)
-Expected maintenance of existing stuff that needs it
-Ongoing maintenance/CapEx (new paint every 5-10 years, new carpet every 5 years, new roof every 25 years, new HVAC, appliances, etc)
-Vacancy (I'd assume 1 month a year, ~8%)
-Management costs (if you want to do it yourself, expected time commitment and what you want to pay yourself). Assume 10% of gross rents here if you don't want to guess.
-Expected legal/insurance fees - probably no tenant will ever sue you, but they can and do.
My back of the envelope on this say you're spending $500 a month on maintenance, vacancy, and management. You still need to pay property taxes, mortgage (if you finance the entire $45k, that's $230/mo at 4.5%/30 year), and some sort of shit-happens number. If we say $150/mo for the taxes and shit-happens, you're at a net of $120/mo.
I would *bet* that if you're grossing $1000/mo on this property you will end up about breaking even (assuming you financed the $45k investment at some reasonable interest rate) or maybe making a tiny bit of money. But it probably compares pretty poorly with just sticking the money in an index fund.
If finding all these numbers and doing the homework seems like PITA, you should not be in the rental business.
-W