The cost of a donut at Tim Hortons can vary depending on the location and the type of donut you order. On average, a plain glazed donut at Tim Hortons costs around $1.00 to $3.49 in Canada, while other types of donuts, such as those with fillings or toppings, may be slightly more expensive.  It is always a good idea to check the prices at your local Tim Hortons before making a purchase.