Flights will depend on where you're coming from, but I just looked up flights on Travelocity from ATL to MCO and you could get a round trip flight on Delta for $135 World's weekend. My only warning on flights is be careful taking an airline such as Spirit just to save a few dollars. If they don't have more than a couple of flights going from your area on a given day, if they cancel, they can put you on the next flight which may be the next day.
As far as hotels, the discount sites (Travelocity, Hotels.com, etc) are a great way to shop, but you have to read the fine print. Many hotels in Florida have resort and parking fees that can up the price substantially. If you are old enough, you can find rental cars for about $25-30 per day that could help reduce your hotel costs by driving out a little further. There are places that offer free shuttles, free breakfast, free parking, mini fridge, microwave, etc. that can help offset costs. We just took a quick Disney trip and the flights at the time were cheapest in Tampa, so we decided to stay in Clearwater Beach so we could enjoy the beach, and rented a car and drove the 1 1/2 hours each way on our Disney days.