Though it seems that most customers are tourists, it helps if you speak Spanish. Our bartender hardly spoke English, so ordering from among an unwritten menu of the night's dishes was difficult. After waiting for seats at the bar, we were expected to immediately place our full order of dishes. We found this a bit frustrating since we felt rushed to needlessly order all at once. This frustration was compounded since the bartender mixed up one of our orders which had been quite clear.
We didn't know any prices until our bill came, but we knew the rough costs before arrival. Each of our dishes were about 15 euros. A total of four or five dishes would probably suit most couples for dinner without leaving completely stuffed. Small glasses of house wine were 2 euros each. We liked the white more than the red.
My advice to new visitors: Take something to write on. Wait in line behind the bar to watch others and see what they order. As you wait, write down which dishes interest you. The easier alternative is to just order lots of dishes until you have way more than you can eat, but your final bill will reflect that approach.