Don't bother becoming a member of Best Fares. My Mother-in-law signed up with them last year to get a *great* discount on 2 airline tickets to England. In the end she paid exactly what she would have if she had booked it herself (ticket cost+Best Fares membership fees). They have a great search (QuickFare Finder) that can help you find low fares.
Your best bet is to know ticket prices and keep an eye out everyday for changes in those prices. I use the Travelocity.com Fare Watcher to email me whenever fares change to/from the cities I picked. I also check cheaptickets.com & expedia.com once a week. Bottom line is you can almost always book a good fare yourself and there is no need to pay any company extra to do it for you (unless you want to).
Another good tip is that when you find a great fare at a site like Expedia, Travelocity. etc, then go directly to the airlines website (aa.com, iflysw.com, etc.) because they sometimes discount rates even further if you book at their site.
Good luck!!! Rates seem pretty good right now. I hope you find a cheap one for your trip.
