The renewal cost next year will be in line with what you have seen with your Norton Security. Over $100. The most economical way is to purchase a new subscription every year. Be sure you turn off the Automatic Renewal that will get turned on by default when you activate the new product key.
This pricing plan is used by many/most subscription based services. You get a discounted price for the first year as a new customer and the renewal will be at the then 'regular price' of the product/service. At least Norton allows us to continue to purchase at the new customer price each year.