This should probably go in the Travel section. Feel free to move it, if needs be.
My best friend is a travel agent for company that does corporate travel. She has access to the same reservation system which most travel agents have access to (I think it's called Sabre).
She can quote a price for the cheapest flight on a particular day, yet I can usually find something cheaper online. Since she is my very best friend, I know she's not lying to me about the price nor is there a "commission" attached to the prices she quotes.
We've found that airlines will often run web specials which undercut the advertised prices for travel agents. Also, as mentioned in the Travel section, you generally pay more for one-way tickets then you will for a round-trip ticket.
Just a few hints from a seasoned transatlantic traveler.
