I will not lend thee a penny.
Why then the world's mine oyster,
Which I with sword will open.
Falstaff:The Merry Wives Of Windsor Act 2, scene 2, 2–5
Not a penny.
If you boast that "The world's my oyster" nowadays, you're claiming that the world's riches are yours to leisurely pluck from the shell. The braggart ensign Pistol, however, utters the phrase as a sort of threat—of the aggressively bombastic kind he's known for. Sir John Falstaff, a braggart almost the equal of Pistol, refuses to lend him a penny; Pistol promises to use his sword, if not on Falstaff, then on other helpless victims, to pry open their purses. Pistol's thievish intentions have largely been forgotten, and "The world's my oyster" has become merely a conceited proclamation of opportunity.