You definitely don't need to use a travel agent. The best sites to use are Bookingbuddy or Kayak. Both sites allow you to compare every possible flight along with which flights are non stop, direct or multiple stopovers. You can also choose by shortest flight time etc.. From these sites you can compare Expedia prices along with Orbitz, Travelocity, Cheaptickets, Priceline and everyother company. Different companies can charge from $100-$300 difference for the exact same flight. They all have different allowances from the Airlines so when one flight may not be available on Oribitz you could still find it available on Travelocity. Check all the different companies once you decide the itinerary that you want.