Eh, that's only true if you are cash rich and time poor. A booster box with 36 booster packs costs ~$100. At 15 cards per pack, that's 540 cards per box. The latest set has 249 cards, so a box will probably get you close to 2 of each card. But to be guaranteed to have all the cards you want, you may need to buy a second booster box and do some trading/purchasing of individual cards. Total cost is at minimum ~5¢ per card.
But I can also just print 6 cards per page from my black and white laser printer at a cost of up to 8¢ per page, or about 1.3¢ per resulting card (plus cutting them out with scissors). And, this doesn't require an upfront payment of $150+.
So no, I would not say the cost of just buying the product is lower.