For sale by owner help

[Brad Ickes]

I am in the midst of a deal currently on a for sale by owner duplex. I am rather new to investing and have more of a construction background than the real estate side. The biggest question and maybe the easiest to most that I have is what is the best way to find the market value prior to submitting an offer for this property? My issue is that I have known the owner my whole life which I feel as though makes it hard to negotiate. I am working with a realtor on other deals so I am not sure if I can ask them what they feel as though it would go on the market for or not. I know this house needs some obvious repairs which the owner either doesn't realize or is in denial of and I plan to have a home inspection done to negotiate off of but am still finding it hard to figure out the baseline. This owner has no idea what the value is and I feel she thinks it is higher than it's worth. Any help on how to proceed would be appreciated.