Negotiations, using the right forms to keep you out of trouble, chasing people to get those forms signed on time, disclosures, comps, wrangling inspectors and re-negotiations and appraisers, managing deadlines - and the list goes on and on.The fact that a good Realtor makes it look easy doesn't mean it is. 

When buying a property like this, whether for rental income or other use you need to have it appraised.

I offered above asking price, property appraised at exactly the offer price.

Previous appraisal $360k. 

The other thing is appraised value.

To other posters point the agents, appraisers, and the bank will establish the property value based on comparative properties (comps).

What I have found is that frequently the county appraisal district enters the street name in some unusual way.

The reports are 40-90 pages long and go through the entire house in great detail.Get an appraisal.

Other options are more expensive, and really require you to hit a home run on the appraisal when you refinance. 

FHA requires us as lenders to use the lesser of current rents in the other 3 units vs. what the appraiser deems market.