You have most certainly never incorporated a Canadian corporation online for $20. That's the fee for filing an annual return for a federally incorporated company; the vast majority of companies are registered provincially.
https://www.ic.gc.ca/eic/site/cd-dgc.nsf/eng/cs06939.html
You can incorporate federally and leave it at that. Extra-provincial registration is required if you carry on business within a specific province.
Provincial/territorial corps are all around $300+, but don't have the $20/year filing fee.