So far I have only noticed the website myvipon.com having Amazon promotion codes outside of the United States, their business model monetizes people who want to advertise their products on Amazon and have the option to submit these deals directly to them. I have not signed up to their service, so I do not know the credibility of some of those promotions and believe it should be legit.
Partytimepromo.com recently expanded support for promotion codes for Amazon Canada, which is not straight forwarded finding promotions among the millions of products, and is very time consuming figuring out if a product has a promotion or not. Generally, I try to add all the new promotions I find every 3 days.
My observation for the different type of promotions available for Canadian products is:
The buy 2 for the price of 1, which means you get 50% off but need to buy a minimum of two products. It's not ideal but if you can find someone to split the deal with, then it might pan out.
Buy 2 or more and get a percentage off, which is an okay deal if you have a reason to buy more than one product. It might be a good situation, to buy a second one to gift to someone eventually.
Percentage off with the promotion code, is one of my favorite type of promotions and is what I generally try to target on partytimepromo.com. It is rather straight forward, and have to remember to apply the promotion code during the checkout process.
Specific amount with the promotion code, is another favorite and is similar to a percentage off. I am not sure which is more appealing to shoppers, as the promotion code could be expressed as a percentage.
Sometimes the products have the option to combine a coupon code with the promotion code, and that is the best kind of discounts I like to find. I do use the help of camelcamelcamel.com to search for the product historical prices, before posting the products with promotions on my website.