Obviously this may not always be the case and some people may truly only need the property value and have no intention to sale, but it is good to educate them on the fact that Trulia/Zillow is not always accurate. 

I lost count of how many times I've seen that happen.You say that you'll only buy if the price is well under market value...but you are unlikely to be the only one bidding (and if you are, be afraid) and the other bidders, likely to be pros, won't sit idly by while a property goes to a new bidder at a huge discount.Finally, yes, taxes are an issue, but in your state you also have to watch out for super-senior unpaid HOA dues, and those are harder to accurately quantify than taxes.

We are meeting with a couple of builders in the area in the coming weeks, to finalize more accurate numbers to make our final decision. 

The next accurate set of financials on the MLS will be the first one I see.

If you have the means to not insure a 50k property that has a loss one time for 10-15k of damages, and are comfortable eating those costs for repairs, then hey, that's the risk you are willing to gamble on, and if you are comfortable with that, then that's fine.

Since Zillow isn't as accurate as the MLS, I always adjusted their sold values by about 10%  - so if they say a house sold for 100k, I'd be a bit more conservative and use 90k as my ARV.  

I'm trying to do an accurate analysis on a potential property, but this is my first and there are literally zero comps.  

I want to give everyone on here accurate and up to date information. 

If you like to gamble you could start trading options. 

I make a lot of offers and even with the e-signatures in software like docusign I don't want to have to "sign" every line for every offer I make and, more so, I don't want to have to check the document to make sure everything is accurate insofar as how it binds me to the offer.