CapEx killing cash flow analysis

[Michael Kissel]

I've been looking for my first rental property in Buffalo, NY area and using the rental property analysis tool from this site to do evaluations.  I use estimates of 5% vacancy, 5% repair & maintenance and 10% capex, which from my research are typical values to use.  Using these estimates, I have not had any luck finding a property that returns an acceptable monthly cash flow, even when putting in sell prices considerably less than asking.  I'm looking at duplex, triplex and quadplex's and shooting for around $200 per unit per month in positive cash flow, which again seems to be what is recommended.

Are my estimates for vacancy, capex, etc too high?

Is approx. $200/unit/month expecting too much?

Or are seller's just that out of line with their asking prices?