Internet Security Renewal Question

I purchased a new HP Compaq computer in July - it came with a 60 day trial of Norton Internet Security.  I am getting reminder notices that the trial is running out soon.  My question is what is the advantage of renewing online with Norton instead of just purchasing the Norton software in a store - especially since it’s cheaper in the store?  (I only need it for one PC.)  Advice would be appreciated.  Thanks.