Yes, sales tax is cheaper in the Canary Islands than in mainland Spain. The Canary Islands, and thus Gran Canaria, have a different tax system than mainland Spain, and the equivalent to VAT in the Canary Islands is the Canary Island General Indirect Tax (IGIC). The general rate of IGIC is 7%, compared to 21% VAT in mainland Spain.
There are also some products and services that are taxed at a lower rate or are exempt altogether from IGIC. For example, food, books, and pharmaceutical products are taxed at a rate of 0%.
Here are the different rates of IGIC:
It is important to note that these are the general rates of IGIC. The actual rate that applies to a particular product or service may vary depending on the specific circumstances.