What do you think? Do you go to them, set up a booth at them? What do you look for?
There is a show on HGTV called Flea Market Flip. Two sets of folks get $500 and have to shop the flea market and find 3 items that they can transform in some way and then they complete to sell the transformed items at a different flea market. The couple that makes the most money on the sales, net of the cost wins. I like the show and have thought that it might be fun to do in retirement, not to make money necessarily, although it would be nice too, but to have a little fun, be creative and a stay social. But it can also be a lot of work, hauling stuff around, in and out of the truck or trailer, sitting in the hot sun or the pouring rain...well they make it look like fun on TV anyway. LOL
I like to go to flea markets, although I try NOT to buy anything - too much "stuff" already.