Answer:
When Tom Buchanan said: “you can buy anything at a drugstore nowadays” He meant that he knew for a fact that drugstores sold illegal products.
Explanation:
The reasons behind this answer are that in the first place Tom wanted to make a joke bragging about his life and what he knew. He wanted the people in the car to know he was a bad guy. To impress them and win their respect by knowing he had experienced in the dark world of illegal products. That is why he said that when Gatsby said that he doubted they could find gas in a drugstore.
