I'm not sure I understand what you're asking. Why not just look at yield? Expected rental income vs property value. Just treat it like a cashflow, discount it back, etc.
Any decent real estate agent can give you numbers on the yield in that area, which should be something you can roughly compare. They can also give you a ballpark on the property price and whether that is fair based on comps.
Any decent real estate agent can give you numbers on the yield in that area, which should be something you can roughly compare. They can also give you a ballpark on the property price and whether that is fair based on comps.