You are missing a basic point here:
How do you know that the LISTING PRICE doesn't already take the repairs into account?
The Sellers have gotten a little smarter lately; they know that if they price it too high, that no one will look at it. As a rule, we are seeing Listing Prices that are designed to attract multiple offers.
If you try to Low-Ball, you will just be ignored:
Have your Reator do a CMA to find out where Market Value is. This should take into consideration the CONDITION of the house as well as the COMP's.
After all; your objective is to BUY the house: Right? not just waste your time.