pricing and bidding

[Account Closed]

I am new to Bigger Pockets and rehabbing, I am located in Orange County NY about an hour North of NYC. Much like everyone else I follow houses on the usual sites: Zillow, Realtor.com, Trulia etc. Recently I noticed that many of the listed Fannie Mae houses are originally listed with prices like: $129K - $149K....however rehabbers have been buying them for about for about $60K even though they never listed for anything near that price. 

So from my "limited research" I was under the impression that you would bid at about 5-10% lower than the foreclosure price, but these bids are about 50% + lower. Using the "funnel theory" should I assume that you should just go around offering super low bids and figuring something will eventually be accepted? Also, I have read where rehabbers submit bids in writing to the listing agent before eligibility on a proprerty, just so the bid is already there when the house becomes eligible. Does anyone have experience with this method?