I am located in the Eugene/Springfield markets. With an address of the property, I can offer further insight as to valuation and offer strategy. I am unsure of city-data.com as a reliable source, other than a potential offer price range likely based on assessor records. Your offer of $115,000 is near 22% from asking price. Moreso, they are asking for an additional $19,000 to do upgrades...so this is confusing...is this new construction? Is the property in poor condition and even financiable in 'as is' condition (aka, $139,900).
You can search all single family & multiple family real estate in the Lane County area at:
Where we receive daily downloads from two mls's that serve a majority of Oregon (RMLS & SOMLS), as well utilize google mapping so you can see what is where, also other useful tools.
I have 15 years of local real estate appraisal experience in Lane & Douglas counties, so I know I can help.