the deal isn't the price, but the quantity: if you need 1,000 pills of any medication, you should be under medical supervision/follow-ups, not buying them like they were groceries.
Generally, sure. As for aspirin, though, if you're a couple on a common low-dose daily regimen, that's 730 pills in just 1 year without a single head or body ache.
Aspirin is dirt cheap in the U.S.