I remember coming to this Chinatown fixture as a kid with my family every weekend, and it continues to be the only place in downtown Toronto where you can buy prepared Vietnamese food. This place is known for their banh mi sandwiches, which are great, but I encourage you all to try their other delights!
For $33 I was able to get two grocery bags full of meals for the week - including fresh banh mi sandwiches, goi cuon (rice paper rolls), vermicelli dishes with spiced pork, and banh da lon (steamed pandan and mung bean deserts). They have so many other delicious things too - I recommend the banana cake, tri-coloured che dessert (in the fridge), banh bo nuong (green sponge cake thingie), banana leaf-wrapped skinny sausages at the cash register, and radish cake omelette.
The only downside is they only accept cash.