Land has a lot of factors that can have a huge difference on the value.  

Not necessarily on interest rate, but on other factors like interest only period, Prepayment penalty and floating rate versus balloon payment.

I think that buying it off-market will save me the 6% realtor fees though I do have to factor in the wholesaler fee.I still would like to spend more time looking at the potential rental income but I don't think I'm too far off. 

. $9,450. 30-year fixed, Interest Rate: 5% Rental Income: $3,900 We will be living in one of the units, but for the sake of the analysis I am going to calculate both units as rental income and factor in my costs at the end.2 Unit: $1,600 + 3 Unit: $2,300 = $3,900/moTotal Expenses: $2,832 Operating Expenses: $1,434/moMortgage Expenses: $1,398/moResults Monthly Cash Flow: $1,067/moMy Unit’s Rent: - $1,600/moOur Cost of Living: -$533 / 2 house hackers = $266/mo.Biggerpockets Property Rental AnalysisIn conclusion, if this house hacking plan is accurate and realistic, I would cut my monthly living costs from $850/mo to $233 (excluding utilities), and would have purchased my first rental property.

I suggested we re-pour the driveway, and factor the cost into the total expenses for the flip, my wife disagrees. 

We are interested in learning how to factor annual Tax Rate and End Value into our equation.Is there another way?

The other big factor he alludes to is also what @Richard Sherman pointed out. 

Matt,Speaking toward the insurance piece, your insurance premiums are going to depend on several different factors such fire protection class code, roof age, square footage, age of dwelling, etc.

Accounting may play a factor. 

You won’t get the volume pricing on materials new home builders get so factor in Home Depot retail pricing on everything too.A half burned down house will cost more to repair than building a brand new house from scratch.