I booked a flight and 12 hours later I got a call and was informed that they couldn't honor the price they charged me and were going to have to charge me more. I had already started booking hotels, etc. to go with the flights. Any 3rd party worth their salt can set up a system that checks prices before actually booking and taking peoples money. I cancelled (their new price was higher than it needed to be) and I'm anxious to see if my refund goes through. They have a BBB rating of F because of refund problems.
(Edited to add: I double checked and because the flights didn't go through they never charged me in the first place. That deserves to be noted and corrected)