inexpensive wine

Spain certainly remains a great source of vast quantities of inexpensive wine that regularly deliver good bangs per buck. On its current special offer price this little Rioja-lookalike from Valencia offers pretty spectacular value.
Well, in a £4.99 bottle a recent investigation suggested it was as little as 15p. The highest estimate I've seen is around 60p. The question is, what quality of wine are we actually getting when we pay just £4.99 for a bottle?