Dealing with real estate agents

[Garrette Becker]

    hello I'm currently new to wholesaling so I have a question about getting help from a real estate agent. 

How could I get a real estate agent to get me a list of people who had listed there property but never sold it and had it pulled from the MLS. I'm only asking because I know its kind of a 2 way street with agents, you ask them for a favor and you should be able to offer them something in return but being new I feel like I don't really have anything to really offer them in return. How do I go about this situation?