Seller finance to get started then refinance shortly afterwards, or are you thinking the whole 5 years?

For income property, you can get good comparables based on the rents paid and costs of the property - if the seller is using an agent that agent should be able to provide those.A lot of these costs may depend on your location. 

One scenario is if I buy a house from a motivated seller and then I rehab it and sell it.

There are still areas where you can find deals but it really depends on what you are trying to accomplish (house hack, seller financing, etc). 

Times that by 12 and divide that by the seller's asking price and you come out with a 10,68% cap rate, which is very good. 

First , the guy you get off craigs list isnt a contractor , the guy swinging the hammer isnt generally the contractor .  

Just wanting some new perspectives and trains of thought on finding motivated sellers.

I was going to offer this seller $20k and assume the mortgage and IRS liens. 

Of course sellers expect negotiating but within market expectations or even a little better.

A lot of sellers don't want to deal with the hassle of selling it themselves.