We are in the Dallas area and we fly American or Southwest. I ALWAYS book directly with the airline on their website. Same for hotels.
Many times, the airlines will have deals online. Southwest advertises special deals on an email I get and when I get that email with discounts, I book all the known trips I know we need for the time period allotted on the special. I plan my schedule and hubby's schedule around those deals sometimes.
I book tickets weekly because we fly a lot, especially for business and when we have a customer who needs to have a meeting, we can't wait for weeks for a deal. I often have to book a flight on Monday for a Thursday flight. I've found Southwest to be my go to for short notice flights.
I've found great deals on Southwest. The only bummer is the open seating but because we fly them a lot, we are A-list and can board first, same with American.
What airline had $455? That does not sound too bad to me. I've heard travel "experts" say to book flights on Tuesdays for the best deal. You might try that.
Also, check the low fare finder on the airline site... It shows you the fares if you can be flexible with your dates which are sometimes lower.