When you use one of the travel aggregator websites like Expedia or Travelocity, be careful of the prices you see, especially from the so-called budget airlines.
These types of websites only show the base price. Many airlines, again, especially the budget ones, have all kinds of hidden fees…like seat selection, boarding passes (how would you use your ticket without one of these?), the weight of your carry-on luggage, etc. By the time they’re done hitting you with all the extra fees, that ticket may be no budget!
Many of the major airlines have some or all of those amenities built into their ticket price. Do a little research to make sure you’re comparing apples to apples (or airlines to airlines as the case may be).