Hi. Welcome. What a wonderful keepsake. It's too bad that your kids aren't interested.
I think that most of the value is sentimental. Closer up pictures -- or a larger version of this one -- would be good.
Yeah, some of the brick red colored ones deserve larger photos. Usually solid-colored marbles aren't worth much money. However, the ones we call "bricks" are worth more than average. Close-ups might help us see if you have any of those.
Maybe someone else can give a ballpark estimate of monetary value. I'm suspecting it would end up well below $100. But I haven't been in the market in awhile.
And maybe close-ups would change minds.