I have to take a trip to Detroit in a month and while I’m there I thought I’d take a quick trip to Canada. What things can I buy legally there that I can’t get in the US? I’ve heard that Cuban cigars are available but I don’t smoke.
Any other suggestions?
Cuban cigars, as you mentioned (you find a lot of Cuban cigar sellers in places where Americans usually go. Gee, wonder why…)
Over-the-counter codeine
Poutine, which probably ought to be a controlled substance…
hmm…
Kinder Surprise eggs.
They’re chocolate egg-shaped shells enclosing a little capsule with a toy in it.
Coffee Crisp.
sigh 
This has nothing to do with legality, just availability, but I hear that cloudberries grow in Canada and can found in stores there, Something I have been completely unable to find in the U.S. since discovering how good they are when a friend brought back an itty-bitty jar of jelly from Sweden.
Mmmm. Cloudberries. They grow in Newfoundland by the name bakeapple''. They also grow in the north of Quebec, and there's a distillery near Chicoutimi that brews a liquor from them, goes by the name Chicoutai’’. Other than that, you don’t see them much, though, except at IKEA 
I’m sure they do grow across the arctic west of Hudson’s bay, too, but they really haven’t been commercialised much, as far as I know.
High flow toilets, (but you can’t bring them back into the U.S.)
You might also post another thread asking about “quick” trips to Canada, these days. A couple of Fridays ago I found the approaches to the Ambassador bridge backed out onto I-75 for over a mile in both directions with semis trying to get through customs.
I don’t know whether that was only that particular Friday, or only Fridays, or only the bridge (the tunnel may have less truck traffic as it goes between the city centers instead of connecting major highways).
I really miss kinder egg suprises, mmmmm and Crispy crunch. But what about wine gums and smarties. Robaxacet ( for back pain), it will turn you into floating limbs. DuMaurier. Traditional Beer. GRAVY!!! and poutine. MonteCristo Sandwiches, Yorkshire Pudding. Tubs full of bulk candy at 7-11. Pot, upto 15 grams in Alberta. Thats all I can think of now but I will update later as it comes to me. I will be in Canada myself in a week.
Kinder Eggs and Aero Bars. Also, some kind of candy bar that is chocolate with caramel inside, kind of like the Caramello but somehow yummier. I love these things and cannot get them.
We have something similar in the U.S. I don’t recall the brand name but I remember that they are fairly expensive and usually have Disney related toys inside.
Mountain Dew without caffeine. In fact, that is the only kind you’ll get.
I think you’re thinking of Wonder Balls.
Caramilk. The chocolate bar of the gods, despite the annoying commercials asking how they get the caramel into the Caramilk bar. You’re lucky the stores in my neighbourhood are closed now, or I’d have to go out right now and get one.
Thanks for all of the suggestions. I will definitely try the Caramilks, Aero Bars and Coffee Crisps (looks like I’m going to blow my Weight Watchers points that week). I’ll get some cloudberries if I can find them. From the research I’ve done, I think I’ll skip the Poutine. I’ll have to check on the legality of bringing things like codeine and Roboxacet back into the US.
A Canadian friend once told me that the “Special Sauce” on Big Mac’s tasted different to him up there. Can anyone else confirm this? I’m probably not going to waste a company paid-for meal at McDonalds. Unless they’re really, REALLY good.
Medical marijuana.
British editions of certain books. I know that I can get Penguin editions of books only published by other publishers in the US. It seems weird to have restrictions on sales of books – after all, there are multiple publishers for many books here in the US, but in the back pages of many Penguin editions you see notices “Not Available in US”. Must have to do with contractual obligations.
I’ll bet you can get the British editions of the “Harry Potter” books in Canada.
UK editions of Harry Potter, yes, and also the Discworld books with the proper cover artwork, as well as other UK editions.
Radios that receive the world standard Eureka-147 digital radio, rather than the US-only in-band on-channel standard.
Smarties.
Electric teakettles.
Coke made with sugar, not corn syrup
Montreal-style smoked meat
McIntosh Toffee Bars. Smack em as hard as you can on a table, it breaks into shards, and when you bite it, you nearly break your jaw trying to get your teeth unstuck. You gotta love it, eh?
Wonder Balls don’t have toys inside though, just more candy.