How long before the water heater, the hvac, the stoves and fridges, and the roof fail?
That will impact your short term costs. (Long term, the rent has to cover those costs. Short term, with a used property, they could break at any time.)
How much down? At what interest rate? Can the owner finance it or do you need to go to a bank?
What are the taxes? Insurance? Other costs? Principal and interest if you don't pay cash?
After you subtract that from the gross rent, and another % for vacancy reserve, property management, and general repairs, how much will you be making a year?
Are you better off or worse off on your cash flow compared to your current position?