Paul and Max walk around at the store.
Paul points to a shelf: Look at that! Swing top bottles are on sale for 2.99! We can use those for our homebrew!
Max: But they are empty!
Max, in the beer aisle: Here are swing top bottles with beer in them, and they are only at 2.75 a piece!
Paul: Buy for 2.75, drink the beer, and sell for 3 to other home brewers!
Max: I always wanted to be a professional beer drinker!