Yesterday we visited a Taverna from 1840 for a small drink before the train should depart. A free choice of different types with "La cuenta" written on the table. For almost 40 years ago the system was even more easy. No figures, only lines to be counted before you left. Now the services has "improved ??" and you will know the paying amount for each delivery.
BTW no chairs at this taverna. Drink till you drop