We were a group of 3.
The difficulty is to choose. We sampled many different flavours before being able to finalise the 3 choices - we went for crema catalana & 2 chocolate flavours. Cost is around EUR 4.
They are really nice - but different people will have different preference of the flavours.
Do pay Gelaasti a visit. The weather in the afternoon in Barcelona right now is pretty ideal for ice cream - not too cold (so that you can still enjoy ice cream) and not too warm (so that the ice cream will not be meeting too quickly). Also, you can have the ice cream while exploring the narrow alley ways in the old town area in Barcelona.