Late last year, Fla. Stat. 501.0117 was held unconstitutional by the 11th Circuit, and was found to have violated the First Amendment as an unjustified restriction on speech. In short, four merchants’ dual-pricing for cash vs. credit card purchases was at issue. Florida’s statute expressly permits cash discounts. In 2017, the U.S. Supreme Court is set to rule upon another state’s law which is similar but not the same.
UPDATE: In March of 2017, the U.S. Supreme Court entered an opinion on another state’s law which had similar issues.