Thoughts on potential deal

[Nick Ferguson]

So I'm looking to make my first "true" investment purchase.  I have one other rental but I house hacked it with owner occupant financing so...  

I have 15,000 in cash available and I've been "driving for dollars" focusing on houses that have for sale by owner signs that may or may not be on the MLS. I'm going through the process of getting pre-approved for financing but I'm looking at seller financing as a backup plan or alternative.

Here is the potential deal in a nutshell.

top bottom duplex asking 70,000.  

Built: 1919

Roof: 20 years but "has had yearly maintenance and patching when needed"

Water tanks: both new in 2016

furnaces: both new in 2014 or 2015

Basement: unfinished

Rents:  Upstairs filled at $600.  Has indicated she wishes to stay.  Market rent probably $625-$650.  Downstairs vacant, being repainted and light cosmetic rehab currently. 

House was purchased in 1979 so I'm assuming paid off.  They are selling because they live too far away to manage effectively and they have 2 SFRs closer to their home. They may be willing to do some form of seller financing. I'm thinking put down as little as they will take. 30 year amortized for 5 years and then full payoff (which I'll refinance to do) is what I would shoot for and try to refi and pay it off as soon as possible after 6 months. If they don't go for that, traditional financing it will be but I have a 2 month "seasoning" period on my down payment money that I just pulled out of my other house's equity. I may lose the deal by then so locking it up to favourable terms with seller financing would be great. 

What does everyone think as far as price you would be willing to pay for something like this?  Sellers have had the house on the market off and on for about 2 years and have reduced price from about 90K previously.  They do seem motivated to sell and all money would be profit I believe.   How much would you all pay, put down, and what terms would you be willing to do?

Obviously, I'll have an appraisal and inspection since I'm not comfortable waiving those things yet.