In other words, there's no simple answer to your question.There are two ways to get a reasonable idea of the cost for a particular build:1. 

Depending on how simple you want to keep it, there are lots of good opportunities to invest in the midwest, the south and some areas in the northeast that can provide good price to rent ratios and very nice cash flow.  

My recommendation is to read the book and then set up a simple spreadsheet where you can start to analyze deals as you come across them.

@Rodney Buchanan the simple answer is yes, there is 100% financing out there.  

This is a great and simple way to quickly build your portfolio from 0 to 4 doors in a short amount of time.

I was totally lost by signing the papers, much much more than I had to do in my own country. 

Some of the simple financing deal structures that I have read involved something like 100% financing from one (or a group) of partners in exchange for x% interest and the first position on the lean or 100% financing in exchange for 50% equity (split with the buyer/manager of the property).Our deal is probably going to be somewhat different.

I'm not trying to sound like the sky is falling but this business is difficult enough when things are simple.  

Start simple.

The owner is willing to hold paper on the property.