I have tried quite a number of wines during our trip so far to Spain and I must say I have found a few things:

• White wines generally are not very nice quite sharp and not a lot of flavour - these are the wines found in bars and restaurants.
• Red wines are generally better with most being served far too cold - maybe this is a local thing?

Generally wine is very well priced and is often cheaper than beer for a similar amount in bars and restaurants.

The best wine I have had so far is Ribera Del Duero - La Planta - 2015 and  it is the wine in our hotels piano bar in Vitoria Gasteiz.  

They are charging 3 euros for a decent glass as well as serving it in a proper wine glass.

Looks like it retails for about 6-8 Euro a  bottle in Spain.