I have almost $50 worth of circulated 68-74 S-mint memorials. I keep every one I find.

I'm pretty sure they won't be worth much more than face value in my lifetime. Or in my childrens lifetime.
I have a granddaughter now.

The coins probably won't be worth all that much in her lifetime either. But she'll know what they are...and where they came from...and hopefully, she'll impart that knowledge upon her children and grandchildren.
