SDCL § 10-45-1.13: De minimis defined.

For the purposes of § 10-45-1.12, the term, de minimis, means the retailer's purchase price or gross receipts of the taxable products is ten percent or less of the total purchase price or gross receipts of the bundled products. A retailer shall use either the purchase price or the gross receipts of the products to determine if the taxable products are de minimis. No retailer may use a combination of the purchase price and gross receipts of the products to determine if the taxable products are de minimis. A retailer shall use the full term of a service contract to determine if the taxable products are de minimis.