Investing is risk, knowing what you are risking and assessing if the return is appropriate to the risk you are taking is crucial. 

If you do a risk assessment of the area, property and likelihood that you can collect rents easily, then you should be good.I have about 25000 saved up and I'm living at home for free how much of that should I spend on a property or save. 

The main variable that jacks up the assessment value is the household income of every neighborhood you find those lots in, I’ve seen lots in low income areas that had a much lower acreage value.

I've had 4 different local RE agencies assess the asset at €580K, €650K, €730K and €800K. 

After assessing the property’s potential, we negotiated a favorable purchase price of $21,000, ensuring room for profitable renovations and a solid return on investment.

There are also nonzero probabilities of having special assessments for a medium-term horizon. 

Also, this is a pretty comprehensive book on the subject: https://www.amazon.com/Subsidized-Comprehensive-Government-F...

Just have 1 unit /condo in chicago loop, that is now available for renting.Posted on Zillow , total of 6 applicants. 2 very interested parties.What tool/website should I use to do a comprehensive background check? 

Both electrical and water meters will need to be assessed by the city via city permitting.

@Gavin Sorensen, like Henry noted, this is impossible to assess.