Oh my goodness, one of our favorite things to do during our 3 months in central Florida.
The Webster one is the king of them all and is on MONDAYS only.
http://www.websterwestsidefleamarket.com/ Also starts early and ends early. If you get there after noon it will be slowing down.
Acres and acres of stuff...unbelievable. Use gps to get there or google map it...it is in old central florida and you need directions. This is 6 hours to see it all!
Our favorite two weekend ones are in Auburndale and Mt. Dora (Renningers). A true flea market is just the weekend!!
These two are huge and loaded with stuff. Mt. Dora has a lot more true "junky" but fun outdoor booths. Auburndale is lots of jewelry, shirts, golf and great fresh fruits and vegetables.
http://www.intlmarketworld.com/ this is about 35 minutes down I-4 east to Toll 570 Polk Parkway. Go about 15 miles to exit 17. Turn east or left on 192 and the flea market is right there.
Mt. Dora is about 50 minutes north...192 west of Disney to Toll 429. Take 429 till it ends and turn left on 441. Go about 10-12 miles to Renninger's on the right
http://www.renningers.com/dora/dorahome.htm Easy to find and Downtown Mt. Dora is really neat with lots of shops, art, and restaurants.
Both of these is 4 hours just to see it all.
Enjoy...Ted