One of the best tips that I can give you is to register with Travelocity or an airline website. You can put in what you are looking for and they will email you when a fare drops.
Here's a list of smaller airlines that fly into MCO. Some of these will not show up on the major travel search engines. I'm not sure how many fly out of IN, but it wouldn't hurt to look.
Smaller Regional Airlines
Alaska Airlines- www.alaskaair.com
America West Airlines- www.americawest.com
Independence Air- www.flyi.com
Jet Blue- www.jetblue.com
Spirit Airlines- www.spiritair.com
Sun Country Airlines- www.suncountry.com
USA 3000- www.usa3000.com