The allowance is $800 per person. If you purchase something of value over that, just declare it and they will charge you the appropriate duty and taxes for the item. Sometimes, they may give you a break depending on the amount over the limit. It is always better to declare it, as if you don't and they suspect and have you open your bags, you could be denied access to travel out of the country and your name will alert them to check on you going forward. Canadian customs is stricter in a lot of ways over US customs. Lots of people as you say don't make a truthful declaration and sometimes get lucky, but it is not worth the risk. Even paying duty and taxes on an expensive jewellery item, you still save money.Honesty is always the best policy!