It was springtime. Elaine's nose was running. Her eyes were itching. She asked Jerry to buy some allergy medication. He went to a drugstore. He looked at the allergy medications. He compared active ingredients. He compared prices. He compared expiration dates. He found a non-drowsy house brand. Each pill lasted 24 hours. Ten pills were in the box. He paid $9 for the box. He took the box home. Elaine took a pill. A while later, she felt much better. Ten days later, her allergy was still active. "I need some more pills," she said. Jerry went back to the drugstore. He took the empty box with him. He couldn't find the boxes with just 10 pills in them. Instead, he had to buy a box with 30 pills. It was the same house brand with the same active ingredient. But these pills were self-dissolving. The box cost only $18.