making offers without seeing property

[Mike Lee]

Hello all, I'm a REI newbie looking for some advice. I'm trying to buy properties in southern california. I'm currently working with an agent to look at houses and found a couple of SFR that interests me. When asked to view the property the request was denied and we were told that property can not be viewed other than just a drive by.

I have a few questions: Is this normal?  How can we buy something without viewing the condition it is in?  

Has anyone here bought properties without being able to see it from the inside?  If so at what percentage of the asking price should I make my offers?  How do you judge if you should pursue the deal.  Are there ways to research or other criteria I can use to help me make a more educated decision rather than just depend on lady luck?

thanks in advance for any help and advice given