1kg meat - 4.39 for decent meat on sale, 6$ regular for the kinda gross meat tubes (probably fairly similar pricing in toronto)
about 1/4 bag frozen corn - about 50c. Or maybe a half? I don't measure.
1 box instant potatoes - 1.77-2$ (ok, you might consider this non-home cooked...I don't care, it tastes better and is faster for an equivalent price)
1 onion - little, maybe 25c
spices - negligible, maybe 10c
garlic - negligible, maybe 25c
I don't like peas and carrots in my shepherd's pie but those are not that expensive, maybe 50c for 1/4 bag frozen peas and 50c-1$ for the carrots depending how much in bulk you buy them.
I usually throw in a "ball" of frozen spinach - negligible, maybe 25c
I also add a bit of cheese to the top - maybe 50c worth or so
(but adding cream cheese and milk to shepherd's pie? weird....)
I do not weigh my food, lol, but I know I can get about 6-8 meals out of a shepherd's pie like that, and I eat a lot (I need 2 frozen dinners to feel satisfied). I won't buy frozen dinners for more than 2$ and they rarely go on sale for less than that (except the really really really gross ones like swanson which go on for 1$ but why even bother).
So my analysis gives me 6 meals for 7-9 dollars vs buying 6-12 frozen dinners at 2$ a pop. And it's delicious . Also this particular recipe is extremely meat-heavy which is the main cost, and it could easily be cut 1:2 or even 1:4 with something like lentils or beans, drastically reducing the price for not much taste difference.
But sure, it's possible (not mandatory) to spend more on home cooked meals than on frozen dinners. You just have to compare the nasty 1$ frozen dinners with decent quality home cooked food, especially with a lot of expensive meat in it. I just don't think that's a useful comparison.