Airline fares make no sense. I can often fly from Miami to LA or SFO for less than $300, but have to pay $600 to fly to Atlanta. And you might have to pay $800 to fly from LAX to MIA the same day I'm going the other direction for $250. Go figure.
You need to check airfares from your airport to MCO, and also from nearby airports and to alternate destinations like Tampa, West Palm Beach, etc. Sometimes you'll find much cheaper airfares by looking at all the alternatives, but you also have to weigh those against convenience and scheduling. I usually end up flying from MIA (even though I could save a few bucks flying from Ft. Lauderdale) just because the flight schedules are so much better. Having an 8-12 hour flight day is not worth a $100 savings to me.
I also don't like Internet travel sites for fare-hunting. I check some of them to see what the lowest prices are, but I usually find that I get the same price and much better scheduling by going directly to the airline's web page.
Many large carriers change their fares very early Monday or Tuesday morning, so the advice above about buying on Tuesday often works out. Do NOT buy your tickets on a weekend. I'm not talking about traveling on a weekend, I mean purchasing the ticket. Fares will usually be higher if you purchase on the weekend.
Southwest is a completely different animal from most airlines and they have their own fare/discount system. If you don't mind flying SWA, some time spent learning their system will save you some money.
I personally avoid the deep-discount carriers because of their cancellation and on-time issues, but many people like them.