There are people who collect lunchboxes. There are many sorts and many different manufacturers. Among the most popular collector items are the rectangular stamped steel boxes made by Aladdin for several decades. But to the point. It is not just the type or the manufacturer, but the individual object that makes all the difference.
Recently, a certain Superman lunchbox in mint condition sold at auction for more than $13,000. But this is not to say that the one you have is a mint, so to speak, waiting to be transformed into cash. Not all boxes are equal, not even all Superman boxes.
Perusing several sources of information recently, I determined that many of the desirable models are selling in the $25 to $100 range, with some going as high as six and eight hundred bucks. (Of course you can list your object on eBay and ask whatever you want; but the chances of a taker are slim. And if you let it go for no reserve, you might get $0.99. Or you might do very well indeed.)
My daughter chose back in the sixties a lunchbox which I still have. Rectangular, metal, fair but far from mint condition. And--- wait for it. It still contains the last used napkin and wax paper wrappers from the last lunch it carried! Am I rich? Okay, suspense over. Hers is a "Holly Hobbie," salable on the market for perhaps five dollars, or in other words, probably about what it cost with Thermos. Given inflation, not a great investment. Wait, it's a lunchbox, not a stocks portfolio.
It proudly occupies a space atop the kitchen cabinets along with the few McCoys and a couple of crocks. These old Crocks enjoy them, and that is all that matters.