Determining the actual value of a house and due diligence?

[Mack Lev]

Alright so I'm in love with the idea of buying property at a severely discounted rate through online auctions. The opportunities seem endless. But Im confused on a number of things.

1)How do you determine the actual value of the house?

-I know sites like zillow and truila exist but i feel like those aren't exact. And I don't want to contact a realtor everytime to find out the exact value but I'm not sure if thats the norm (Im still a novice at this). And if i do have to contact a realtor for exact figures do I have to use one for that area or can I just use someone I already know locally?

2) When doing your due diligence what do you look for? And are all liens wiped out through the foreclosure?

- I know checking the county website will tell you alot but is there anything else I should look out for? Again these online auctions are for properties out of state so I would have to be calling the shots from afar. Im willing to make trips if needed but the idea is not too, if thats possible .And my primary strategy is to sell as is. Since the property was already severely discounted why bother with fix up? Get in get out is my strategy.

Again thanks for all comments, opinions and suggestions, and advice.

-Mack