which method most useful for foreclosures?

[Kyle Allen]

The sticky on the otp list several ways to locate foreclosures but i was curious from the members which sites and methods have worked best for them.  I have found several websites that provide this service for a fee and have not issue paying for this but what i'm learning in my area is we have a few realtors that are buying up properties immediately (tax and sheriff sales) and the notices are very vague about when the auctions occur.  One house in particular i did a ton of research and was told be several that the bank hadn't done anything with it then found out two days later a realtor had purchased the property for tax sale for 1800.  This is becoming increasingly frustrating.  Another was a bank foreclosure and the house was listed at 9900.  However after making a full price offer the bank sold to another client for more money.  In bank foreclosures is it common for these house to be sold over what they are asking?  Do my offers need to be over market value of the selling price?  We have 3 rentals and are finishing a flip but could greatly increase my margins by getting these low price properties as i do the work myself.  Thank you all in advance for your responses.  It is greatly appreciated.