Starting with PI how can I determine TI?

[Brian Kempler]

Scenario is that you're trying to calculate a potential buyer's monthly payment to you at various interest rates. Easy enough to derive PI from that, but how do you find TI (taxes, insurance)? 

- My theory of taxes for the state of Ohio is to see what property taxes are for a given county, and divide the rate by 12. Then multiply this monthly number by the total sales price.

- Insurance: Not sure. Any techniques you guys use including ballparking would help, thanks.