I grew up in Montana, a couple hundred miles south of the Canadian border.
It wasn't rare that we'd get Canadian coinage in our change. Some proprietors didn't care about the subtle exchange difference and took it as legal tender for small transactions ("shit, Joe, all's I got's this beaver nickel. You all right with that?"), taking the small hit one day and passing it off on some uncareful client the next.
Usually it was pennies and nickels, but every now and then you'd find a Queen Elizabeth quarter or, if you were really lucky, a golden Loonie. It's always struck me as cool that the Canadians emblazoned their coins with birds and beavers and caribou instead of buildings. Much more nature-bound, more at one with the Earth. I will say, though, that the Lincoln Memorial is one of my favorite buildings on the planet and I'm more than bummed that they've taken it off of the penny.
From the time I was ten or so, I hoarded Canadian currency. My mother was my more reliable source. She owned a comic book store for several years, one of the biggest in the state, and she never had to accept Canadian coins at a loss because she knew that I'd make good on my promise to buy them off of her at the end of the day, offering a cent-for-cent exchange with money made in the good ol' U. S. of A.
I kept my stash in a bright orange plastic pencil box with a cartoon classroom scene drawn in bold bright colors on the lid. It grew heavier as my hoard got bigger. It was mostly coins, but every now and then my dad would take a business trip to Waterton Lakes National Park or Edmonton or Vancouver and he'd come back with a few spare bills.
I'm really not sure what I meant to do or make in amassing my collection. I had no numismatic urge, and I'm pretty certain that I knew I'd never get rich off of it. Maybe I had vague dreams of traveling to Edmonton to drop it all at the West Edmonton Mall, a thoroughly appropriate fantasy for a child of the '80s. (Even back then they had an indoor water park!)
When I moved away to college I cashed it in at the bank, giving me around a hundred bucks, American.
I live much farther from the border now. Every now and then I find a leaf-backed penny, and as rare as they are (and they are, especially since discontinuation) they're far more common than their more valuable cousins.