Being on the west coast, it is a lot more expensive to get down to Belize. I paid a little more to fly out of Sacramento so I could avoid 2 hour drive each way to Bay Area - my flight this May on Continental is a little over $600, which I booked on the net (after checking it many times until I found that lowest fare). I only have 20 mile drive to airport and Sac is so convenient to get in and out of.
Well, us folks on the west coast do have an advantage. If we go to Mexico or Hawaii, the fares are cheap!