When I was young, I "learned" that the white man ripped off the Native Americans (or maybe we called them Indians back then, I can't remember) by buying Manhattan Island for $24 in trinkets. Well, that overlooks the time value of money. If you invested $24 in 1626 and earned an annual return of 6%, by 2008 it would be worth over $111 billion.
Now maybe that rate of return is too high, but clearly it's absurd to look at the 1626 purchase price and draw conclusions.
(Here's Cecil on the matter.)