US pricing does have a direct affect on pricing here in Canada but this relationship is quite complicated. Here are some thoughts:
1. There is a huge advantage in picking up a machine locally, one that you can see and touch before you buy and many will say this is the only way to buy a pin. However, IF can get over the great number of inconveniences of having a pin shipped (misrepresentation of quality of pin, financial risk from payment to stranger, damage risk from shipping, substantial shipping costs, paperwork, long wait time, etc.), THEN local prices in Canada can only be a certain amount higher than US prices and no more. Because at a certain point, you can just order the game from the US, which in my experience is about $1000 CDN for a single pin when all is said and done (shipping, customs broker, GST, payment fees).
2. Time is money. If there is a pin you really want, you could wait 20yrs to have it show up on the local market or it may never show up. Then when it finally shows up someone else buys it immediately. Waiting is not always an option depending on how many machines there are available locally.
3. Local prices can be much higher than US prices if local demand is much higher than local supply. But this is only true up to a certain price point since people will just rather ship it in. The thread you are reading is for pins available for sale in Canada and just count how few pins come up in one month - very few. If a nice pin comes up at a reasonable price it will be gone in hours and this is across all of Canada.
Come to think of it, there are so few pins available to buy that in a thread titled "Anybody in Canada have any pins they want to sell?" mostly what we do is talk about prices (I'm guilty here too ). This is how much local demand exceeds local supply. Therefore we can expect local prices to be quite a bit higher than US prices in some cases.