One of the most underrated holidays in the state of Texas starts Friday.

From Friday, Aug. 10 through midnight Sunday, Aug. 12, most clothing, footwear, school supplies and backpacks can be purchased tax-free from stores or online businesses. In most cases, you do not need to give the seller an exemption certificate to buy qualifying items tax free, the state comptroller’s office says.

The exemption only applies to things you buy during the holiday weekend, so you can’t get a tax refund for something you already bought. You also can’t get the tax exemption for items that cost more than $100 or items that are specific to a certain activity or sport.

For example, golf cleats and football pads are usually worn only when people play golf or football, so they do not qualify for the exemption. Tennis shoes, jogging suits and swimsuits, however, can be worn for other than athletic activity and qualify for the exemption.

Backpacks and some school supplies qualify for the exemption, but purses, duffel bags and luggage do not. The full list of items that you can buy without paying sales tax is available here and goes into detail of which items fall into each category.