JACKSON -- Shoppers in Mississippi can save money this weekend based on some constitutional rights.

The Second Amendment weekend takes place today through Sunday. Guns, ammunition, archery equipment and many other hunting supplies are exempt from the state's 7 percent sales tax.

Named for the constitutional right to bear arms, the exemption was passed by the Republican-led Legislature with bipartisan support and signed into law by Republican Gov. Phil Bryant in 2014.

Even without a state law, a store in Oxford is offering a 7 percent discount on books the same three days.

Square Books will collect the state sales tax. General manager Lyn Roberts says the discount, equal to amount of the tax, celebrates the First Amendment rights of free speech.

Roberts says this is the second year for the store to offer the book discount during the Second Amendment weekend.

"It's not against that," Roberts said, but is way of honoring other constitutional rights.

Mississippi and Louisiana are the only states with sales tax holidays for firearms, ammunition and hunting supplies, according to the Tax Foundation, a Washington-based group that analyzes federal, state and local tax policies. Louisiana's is Sept. 1-3.

The foundation says 16 states have some sort of sales tax holiday this year on various items, including school supplies and disaster preparation supplies. That is down from a high of 19 states in 2010.

The foundation advocates lower taxes and criticizes sales tax holidays as a gimmick.

"Most sales tax holidays involve politicians picking products and industries to favor with exemptions, arbitrarily discriminating among products and across time, and distorting consumer decisions," analysts Joseph Henchman and Scott Drenkard say on the foundation's website.