Capital Expenditures are all the major items that eventually break.If you think about turning this into a full scale investment property you need to consider several things.  

As impoverished people leave the city and middle/upper class move into the city, the city's required expenditures decline and the city's tax revenue increases.  

I am paying more than I would like but the market supports the purchase price and we will live in one side which reduces our current monthly expenditures by 80%.

Property taxes, insurance, landscaping, capital expenditures,?

That represent a 18% cost which is pretty high and not sustainable in my case.In another blog for a similar property he takes a 5% estimate for capex expenditure, which is not compatible with the first number at a first glance.I understand that capex increase when the house get older.

What I like about it is all exterior maintenance is covered so it limits my capital expenditures to really only the Hvac system which I put in new when acquired.

Cash spent in order to purchase and improve your inventory is still just that - inventory expenditures.  

If the area is attractive and you anticipate that you will be able to fill the vacancies with good tenants at good rates and with minimal TI expenditure, it's worth figuring out a way to make the deal work.If they are in a declining competitive position with aging buildings and no underlying land value, you are being offered what Warren Buffett calls a cigar butt.

If 80K should be acquisition cost currently, I may be able to squeeze by with a 70-75K offer and Mortgage to include for all of these expenditures.  

While I'm assuming you won't face some of the capital expenditures (CAPEX) that a SFH would, maintenance expenses are typically the wear/tear/replacement/repairs of items/services inside the home.