Since the cost of shipping especially in Canada has become ridiculous lately I have been buying up the Small Canada Post Flat Rate Boxes at the post office. Before to ship a small bubble envelope with some jewelry costs me $25.00 & up from B.C. to other provinces. With the prepaid box it costs $18.49 plus tax to ship anywhere in Canada. I know it is overkill with a box just for a small item but it is worth it when you compare the cost difference. For larger items the post office has a medium size box ($23.49 plus tax) & large size box ($29.99 plus tax). Thought this might help other sellers out if looking for a cheaper way to send across Canada.
You are correct, there is a some limit but you still can send items that fit in the envelop. Recently I sent a watch in a box on a prepaid xpress large envelop and the thickness was about 6.5cm, it went through and delivered with no issues.
