Somerfields/Co-Op have a 2004 Reserva Rioja for only £2.99, this is a bargain, they are normally twice this price.
It is called ALMENA REAL. I tried a bottle last night for research purposes! I drink a lot of Rioja, and for the money this is very drinkable. Not as smooth as some, but you are talking paying £8 to £10, but for every day drinking, very pleasant indeed.