If you don't stick to the tourist spots, but look for some more interesting restaurants, you can have a good meal for 8-10 euros p.p. But remember that Spanish people don't eat before 21.30 (and that is early). But restaurants are opened between 12.30/13.00 and 14.30 for a first big meal. In between these hours, you have to go with Tapas (not a punishment !!!). Normally in Spain, I stay with a friend, and we both like to cook, so we don't eat out that much, but if I remember alright, those were reasonable prices (but because she lives there, she knows, where to go for a cheap bite and where not)
In more touristic areas, you also find restaurants, that are opened on time, that are more usual for the tourists.
Drinks can vary a little bit in normal bars 1.75-2.50, when ordering a Whiskey/Cola in a club, you are likely to pay a lot more (but hey, that are two drinks!)