Hand-waving numerous details, but - That $37 isn't the price in the hospital's gift shop. It's n=1 pricing, hand delivered to your bedside by a nurse with a whole hierarchy of higher-level medical & admin staff behind her, and documented out the wazoo. Aspirin could be free & unlimited at the hospital pharmacy's receiving dock, and it wouldn't affect the @bedside price.
... and in other countries, medical administrative costs are far lower because they don't need to build entire divisions around correctly coding the same condition and procedure 11 different times before insurance approves it, because the insurance is universal and self-consistent by comparison to our private fractured mess.