I can’t find comparables

[Danren Jones]

I’m in process of buying a multi unit building the asking price is a little high I feel for the neighborhood. The building is currently fully occupied with rents below market value. Also there is room to raise the rents through small upgrades. My only problem is idk what to offer because there hasn’t been any recent comparable sales in the neighborhood. If I offer full asking price I still cashflow about $150 per unit And there are 4 units. So should I just make an educated guess on my offer? Advice is greatly appreciated thanks BP family.