You'll never know what rolls will bring in the future. For example some of the shocker rolls that I have seen are the Korean 50 whan minted in 1959, still in it's original roll. If I am not mistaken, there are about 50 coins in there and realistic speaking if each of them were to be broken up and sold, maybe 4 dollars or so. The final sales ended up to be some 400 dollars or something.
A partial Japanese 10 sen coin roll, yes, from Meiji era perhaps 20 or so in it still with it's original rice paper roll (almost impossible to find) would be probably 70 dollars each but ended up to be more than 3 thousand just for that paper roll.
But again, that's after 50+ years. Would be good for your grandson really.