All of the gold and silver coins will have his portrait, as the issue of gold and silver coins was the personal prerogative of the emperor. Bronze coins were issued by the authority of the Senate, not the Emperor; their design was up to the Senate and/or whoever the Senate appointed as their mintmaster. Some Senatorial bronze coins issued during Caligula's reign have his portrait, others do not.
As a very general rule, bronze coins with his portrait are going to be more expensive than those without, but for many collectors (myself included), portrait-less coins are all we can afford.
Roman Provincial coins of Caligula will also often have the "emperor's portrait", but how good a likeness this is is questionable as there doesn't seem to have been a universal standardized official coinage portrait of Caligula circulated out to the provinces, as there was for many of the later emperors. So while the provincial coins might have a "portrait of Caligula" on them, Caligula's appearance varies wildly; for a portrait that actually looked like him, you're better off going to the Roman Imperial issues.
As a very general rule, bronze coins with his portrait are going to be more expensive than those without, but for many collectors (myself included), portrait-less coins are all we can afford.
Roman Provincial coins of Caligula will also often have the "emperor's portrait", but how good a likeness this is is questionable as there doesn't seem to have been a universal standardized official coinage portrait of Caligula circulated out to the provinces, as there was for many of the later emperors. So while the provincial coins might have a "portrait of Caligula" on them, Caligula's appearance varies wildly; for a portrait that actually looked like him, you're better off going to the Roman Imperial issues.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis

















