How Sales Tax Affects Reselling Profit
GST/HST on your purchases and sales changes your real margin. Here is the general picture.
On purchases
You pay GST/HST and, in some provinces, PST when you buy stock.
If you are registered
Registered businesses can generally claim back GST/HST paid on inventory as input tax credits, and must charge it on sales.
If you are not registered
Tax you paid is part of your cost.
Marketplaces
Marketplaces may collect and remit tax on some sales. How this applies depends on your registration.
Get advice
Tax rules are specific. Confirm your situation with an accountant or the CRA.