The collection of poll taxes in national elections was prohibited on January 23, 1964, with ratification of the Twenty-Fourth Amendment to the Constitution. Passage of the amendment affected voting in Alabama, Mississippi, Arkansas, Texas, and Virginia.
…reaffirmed the simple but unbreakable theme of this Republic. Nothing is so valuable as liberty, and nothing is so necessary to liberty as the freedom to vote without bans or barriers…There can be no one too poor to vote.
Source Library of Congress