Something I've had to explain to far too many people recently: any money injected into the american economy is directly aiding the orange toddler and his pals.
His approval rating relies on economic performance, among other things. If you give them your money by purchasing products (regardless of the political stance of the company), you are improving american economic performance, which makes him look better.
The better he looks, the longer this lasts. The only way we'll be rid of him is if the american populace at large feels the economic pain. They won't do a thing until it hurts their pocketbooks. Look how many rabidly supported him until they had to pay through the nose for diesel. They're fine with war crimes until it makes them suffer.
This is why even a single cent is too much. The "do what you can" attitude is a cop out, either you care enough to put forth the effort to find an alternative (or do without), or you don't.
For my fellow Canadians, you would be actively enriching the very people who are putting thousands of your fellow citizens out of work. I wonder how you would feel if it was your job on the line? Would you be ok with other Canadians sending their money to a hostile nation then?
You can do without. If there's a product you can't find a non-american alternative for, then you don't need it unless it's a life-saving medication or treatment. Everything else is just want, not a need. I have spent almost two years doing without a great many things, and I'm just fine. I've found other media to watch and I've saved a ton of money not buying crap I didn't need in the first place.
It may be a cliche, but it's true when they say that the only thing required for evil to triumph is for good people to do nothing.