I bought tickets on AirTran, not Southwest, but let me share with you my VERY surprising experience. I was going back and forth between USAirways' website and AirTran's website, comparing times and prices. I wrote it all out on a chart to help myself compare better. Before I bought airfare, I called Disney to change the dates of my resort reservation. The CM happened to ask me if I wanted her to check on airfares for me. I told her I had it under control, but she could give me info if she wanted. I told her the flight numbers I was interested in. For my preferred USAirways flight she quoted me a price about $5 cheaper than the website (INCLUDING any fees), but the real shocker was that she quoted me a price for AirTran that was about $130 per ticket LESS than AirTran's website's prices, for the exact same flight.
I couldn't believe it, I thought there was some sort of mistake. I went back to the website while I was on the phone with her, just to make sure there was no mistake, and there wasn't. That phone call saved me $520. Made me not care as much that I didn't dig to find CRO's 800 number!