Like $15 per firearm registered, and $100 every three years for a Chicago Firearms Permit. Well, we used to have poll taxes in this country, which you had to pay to vote (and at least partly aimed at the same group that Chicago's law is aimed at: black people). While it took an amendment to the U.S. Constitution to abolish poll taxes as a condition of voting in national elections, in Harper v. Virginia Board of Elections (1966) the U.S. Supreme Court struck down poll taxes in state elections as violating the equal protection clause of the 14th Amendment--and uses "fundamental right" to describe the right to vote.
I think there's an argument here that the right to keep and bear arms is even more fundamental than the right to vote. Voting is limited to citizens, while "right of the people" is considerably broader.