Asda are selling in store and online Taylors 10 y/o Tawny for £5. This may not be everyone's favourite but this is a fantastic port and a great price. I took 16 bottles out of Aberdeen Asda.
This normally retails around £15 and is better than the Warres Optima in supermarkets at £12-13 for 50cl.
stock up while you can. It will last for years if stored properly.