So you’ve found what looks like an amazing deal on something from outside of Canada. You may be correct, but the price you see isn’t necessarily the price you pay.
Firstly the price is very likely to be shown in US dollars not Canadian dollars. Depending upon the conversion rate that might make it more expensive then you thought.
Secondly the price doesn’t generally include shipping it to you. And all the best offers you see of free shipping typically work only within the US or other region local to the R/C warehouse you’ve found. Shipping isn’t normally that expensive for R/C parts, but if a battery or a liquid is part of the order then the price usually goes up substantially as it has to be mailed as a “dangerous item” using a courier like FedEx or UPS. Where possible try to choose regular mail (USPS, Canada Post, or the normal mail service of the country you’re ordering from) and although it might take up to a month to arrive it will cost you less, and will likely not be subject to as much scrutiny by the border officers of CBSA (next paragraph).
Thirdly whenever anything comes across the Canadian border then it is assessed by the Canadian Border Services Agency (CBSA) to determine if any additional import duties are to be charged or only if the taxes are required to be paid. What you have to pay depends upon what description and value is marked on the box by the sender, or whether it is a gift. The description is looked up by the CBSA officer in the Customs Tarriff to determine what duties and taxes should be charged. Any description with the word “toy” in it shouldn’t be charged anything but the GST tax (15%) on the value listed on the outside of the box. A box that is marked “car parts” or just “parts” would likely be charged some duty (5-8%) and then the GST tax on top of that (15%). A package with a battery in it, particularly if it’s a LiPo, will likely be charged some duty (5-8%) and the GST (15%). If the package is small, arriving via regular mail and under something like CAD40, then it would normally not be looked at in detail by CBSA and often proceeds to your mailbox without any additional charges. It is against the law to import a package that is undervalued or marked as a gift when it isn’t. But plenty of sellers will do that anyway as they know import charges are a concern for buyers.
There are a few websites that try to predict what will be charged when it crosses the Candian border. This is one has been helpful in the past: http://www.dutycalculator.com/new-import-duty-and-tax-calculation/
In summary, and from personal experience, we find that it is most effective to buy batteries and vehicles locally, or within Canada. But that substantial savings can be had when buying hard-to-find parts and supplies in low value orders from outside of Canada.