I tried to sell one last year that was similar. It was older, but it was in far worse condition. I didn't have any luck at $20 when I tried. And contrary to what the "expert" said on Auction Kings once, having the thermos DOES add to the value. I don't know if this one even came with a thermos, but if you have it and the rubber seal is still intact, then that will increase the value. Being a miner's lunch pail, and knowing what mine it was used in helps. There is one pail of the same manufacturer on eBay right now that has a $10 bid on it. You're appears to be taller, and the eBay one was clearly polished. Assuming the condition is still good, I would venture a "not-so-expert" guess of at least $50 for it.
More pail collectors like TV shows, musicians, and old movie ones that kids used to carry. I got $60 for an old banged up Aladdin pail and thermos last year that had Zorro on it. Pictures of the inside and a description of the condition would be quite helpful as well.