NIS 2009 Upgrade or New?

My NIS 2008 subscription (which I have upgraded to 2009) is due for renewal in January, my question is if I renew online via Symantec it will cost £38.97 but if I buy new from say Amazon, I can get it for about £22, but there seems to be a new one and an upgrade version, but the specifications look the same, anyone know what’s the difference?