First duplex investment

[Angel Trujillo]

I’ve got what I feel like is an awesome opportunity to buy my first duplex. First the pros. The 3 bed 1 bath unit needs all new everything. Rent is only 750 a month so There is room to go to 1100 based on surrounding rents, it’s 750 because my wife’s grandma has lived in it for the last 40 years and they didn’t want to raise rent too high on her. It’s got the original kitchen from when it was built (the 50s) carpet in the living room and bedrooms and laminate in the kitchen. It has a staircase that takes it downstairs to the unfinished basement where the washer and dry are. The unfinished basement is as big as the upstairs. Also there is an unfinished half bath. The basement has a door to go outside. Making me think of making it a separate unit in the future. The rear unit is basically the same story. This unit rents for 1000 a month. The owner took out the staircase and moved the washer dryer upstairs. So the rear unit has to go outside to get down to thier basement. Making it a little easier to make this basement another seperate living space also. So the duplex as is makes 1750 a month in rent. Property tax is 3100 a year and insurance is 1400 ish. The house needs a new roof which was quoted at 12k. My problem is is that the owner seems to want to get market value of the property.250-300k  Working the home backwards using rents I budget 140 per month in Vacancy, 80 for maintenance. 80 for cap ex and 200 for property management. I estimate 225 will be an ok price to pay with 3% down Mortgage tax and insurance will be 1295. Rents 1750-1295(mortgage) -140 vacancy-80 maintenance-80cap ex- 200 property management which we will do ourselves for now= -45 dollars but since we will pay ourselves the property management fee until grandma moves out and we can up rent we will be making 155 per month. Is there any other way I could make this work?? I tried private financing over 15 years but I would only be able to give him around 900 a month and he’s making 1350 now.... purchase price only around 130k with 4 % making it about 172k after 15 years. advice is appreciated.