I tend to do a lot of research on the net using Expedia or Travelocity, then I ALWAYS go to the Airlines OWN web page and purchase my tickets there. Airlines have been cutting back on
Travel Agent commisions and eliminating them in some cases because they can sell their tickets other ways. Many airlines will give you a discount on the cost of the ticket by using and BUYING the ticket on THEIR website. For example, I was looking for tickets for my Brother in Law to go to Florida next month. Travelocity and Expedia were quoting 148.00 plus tax for the tickets. Went to the airline's webpage (ATA in this case) and quess what? The same tickets were 100.00 plus tax (125.00 including all fees). I bet if I had called ATA on the phone they would have cost more. Last summer I paid 138.00 R/T for tickets on their webpage. Just to double check I called their 800 number. The same tickets, SAME FLIGHTS via their 800 number were 200.00 a peice.
Bottom line, use the airlines web page if you can. You get the best deals that way, at least for now.