when it comes to groceries, dollarama is actually usually a brutal ripoff, and what it sells has low to zero nutritional value.
the cheapest grocery store in canada for almost everything is walmart, but i also buy specific items at freshco, superstore and food basics. giant tiger is worth shopping at. if you can buy in bulk at wholesale or get into costco for free, you should. you want to avoid dollarama, shopper's drug mart and zehr's, usually, although they sometimes have sales. bulk barn is also often a brutal rip-off.