There are tonnes of restaurant supply stores around. If you are making a volume then maybe Chef’s Depot at Markham / Finch? I didn’t look at baking supplies when I last went though.. but normal consumer retail the above suggestions like The Bay, dollar stores, kitchen stuff plus, Walmart, Etc.
Even amazon - something like these maybe? Freshware CB-305RB 12-Pack Silicone Flower Reusable Cupcake and Muffin Baking Cup, Black and Red Colors https://www.amazon.ca/dp/B009ANCUCO/ref=cm_sw_r_cp_api_i_Nk1.DbQABSPZ0