If it is a fix and flip, you need to know what $$ you will need to get it market ready and what will it sell for when completed.
If renting, you need to know what rents are in the area for similar home.
Not sure what you mean by value. Usually value = price. That is how values are determined.
Assuming the $650k value you give is for a home in reasonable condition, it would probably be in the 80% range, so $520,000. An investors profile is finding homes that need a little work, spruce them up and sell again.
just carrying costs 2% and realtor commission 5% will be 7%.
I hope that typed out right...............if you need anything at all just ask
Century 21 Northshore