How we cite our quotes: (Story.Chapter.Paragraph)
Quote #1
"No-oo. But magic of a kind, I think. Not the usual sort. I mean, [sound-as-of-underground-spirits] can turn gold into copper while at the same time it is still gold, it makes men rich by destroying their possessions, it allows the weak to walk fearlessly among thieves, it passes through the strongest doors to leach the most protected treasuries. Even now it has me enslaved—[…]." (1.1.57)
"The Color of Magic" satirizes the value we put on gold (it's just a metal, people). The satire centers on the fact that Rincewind can only think of gold's power in terms of magic, and it's an oddly accurate way to do it.
Quote #2
"Um. Is everyone in the Agatean Empire as rich as you?"
"Me? Rich? Bless you, whatever put that idea into your head? I am but a poor clerk! Did I pay the innkeeper too much, do you think?" Twoflower added. (1.6.14-15)
Rich for one part of the world isn't exactly rich in another part. Being rich is more a relative term, as in relative to the wealth of those around you.
Quote #3
"I may as well tell you, Rincewind, that there is some contact between the Lords of the Circle Sea and the Emperor of the Agatean Empire, as it is styled," the Patrician went on. "It is only very slight. We have nothing they want, and they have nothing we can afford. It is an old Empire, Rincewind. Old and cunning, and cruel and very, very rich." (1.7.37)
The differences between the Empire's society and Ankh-Morpork are so great that they have very little contact with one another. Thanks to Twoflower's arrival, though, that's about to change and both the societies will shift along with it.