Did you include the cost of having a trained medical professional administer them? The cost of hospital aspirin isn't the pill it is the doc deciding to give them to you and the nurse who dispenses the pills( don't forget the billing person who charged you for the pills, the staff lawyer who was retained just in case you sue over the aspirin, and the payout to the last guy who sued and won).

As with every service industry from the local pizza joint on up COGS(Cost Of Goods Sold) is one of the smallest parts of the pricing puzzle.