I can't think of nothing right near the House of the Mouse. You will have to get out to near by community's for that type of hunting. Clermont, Occee, Kissimmee, Winter Garden, Winter Park.
Look up Goodwill, or salvation army stores then just map then out to see which are doable.
I do have another thought, If you are here on a Monday, you can go to Webster it's a huge flea market but only on Mondays. Maybe a hours drive or so. Lots and lots of stuff to see. There are some vendors that have Disney related items, I picked up several booklets of old paper tickets that still had "E" tickets in them... they have the regular market, and then have what they call the field, where you can rent a space for the day, its like a bunch of yard sale packed together... Go early, most vendor take off by 2:00...