Probably depends where in Canada that you live - in many places is simply NO Large Rifle Primers to buy, although they are slowly trickling in for some stores - and when you find some, expect to pay $0.30 or $0.40 each. Powder supply seems to be variable where I am - circa $60 to $90 per pound? Bullets is pretty much what you want to spend - plated versus jacketed versus cast lead - .311 or .312" diameter - weights commonly 150, 174 or 180. - might assume $75 per 100 bullets - others will make different choices and have different prices and availability where they live.
So, as above - $0.35 per primer. $90 per pound powder = 7000 grains. If the loading that you chose follows Hornady loadings, perhaps 40 grains per load with some powders - more or less with other powders - so 7000 / 40 = 175 loads per pound - but you are going to buy a pound, most likely. That works to $0.51 per round for powder, at $90 per pound. The prices above show $0.75 per bullet - they typically come in bags or boxes of 50 or 100 - so, $0.35 (primer) plus $0.51 (powder) plus $0.75 (bullet) = $1.57 per round. Times 20 rounds in normal box = $31.40 per box in components to make your own. Compared to $45.00 purchase, you get $13.60 per box to buy reloading gizmos, pay your time to reload, etc. However, regardless how many rounds you plan to reload, is probable that you will spend at least $35 for 100 primers, at least $75 for a pound of powder and at least $38 for 50 bullets - so you will spend $148 to buy minimum (or typical) quantities of each component. Some might find buying 3 boxes of shells at $45 each to be "cheaper".