There are several in my area, and they have been a mother lode of used items at good prices. Several have FFL licenses and used firearms are always available. Some of their prices can be near retail, but there is enough competition to keep prices in check.
Got several knives at great prices, and after scrounging through a pack of old coins, found several pieces at below spot.
Haven’t done the flea markets, so not sure what is available.
Every year Indiana University sells what has been left behind in dorms, and the prices are unbelievable. But you have to get there early. Neighbor got a fully functioning laptop loaded with Microsoft Office for $25.00. Took a little getting all the headbanger stickers off.