At the same time, 10% vacancy is probably not accurate to your market, so why are you underwriting with that number?

Contractors can be fickle people, but sometimes you're forced to take a bit of a gamble

A really cheap property that needs a lot of rehab has to be managed.You also need experience rehabbing,Material shopping, permits, managing sub contractors, order of operations, managing payments, checking work, and accurately projecting all of those numbers in the first place to make sure you get a good deal.Best bet is to buy more of a turn key rental for your first purchase.

Find three houses that are similar to your residence, and the average of those three houses should give you a fairly accurate rent. 

So if you put in $27k and (assuming your numbers are accurate) it is paying you $7848/year, that is about 25% cash on cash return. 

I am new to real estate investing, looking for my first project and wondering what the most accurate way is to run comps on properties.

Perhaps I am way off and your calculation is much more accurate. 

If you are using numbers that are guesses, or hopeful....then you wont get an accurate picture of what the true cash flow is.

Is that accurate?

How do I get an accurate value on what it is worth?