Conversation classes in English or German

I am a student studying Media Sciences in Germany and I have just finished an Erasmus semester here in Madrid! I am offering conversation classes in English (my mother language) or in German (which I have learnt over the past 7 years). The classes can take place in a Plaza or café, preferably in the center but that is negotiable.

You decide: would you prefer one-on-one classes or to work in groups of a maximum of 3 people?

My availability is only until the 5th of July, after that no more classes will be on offer.

One-on-one classes: 12euro per hour
Groups: per person 10euro