Very cheap, very clean, very friendly staff. Quiet neighborhood, quite close to the city center.
If you can't allow yourself investing more than 50 bucks per night for a Berlin hotel, "Am Hermannplatz" is your choice. The hotel is basically two floors of a 4-floor building in a residential area, renovated and remodeled for a hotel. The entire staff is one front desk clerk and one custodian. The clerk speaks decent English and he is the one who will bring your breakfast to your room in the morning (they don't have any dining space). All the amenities are _very_ basic (a double bed, a small bathroom with a shower stand, a small TV and a telephone, a closet, a table and two chairs), but it looks like the room has just been repainted and even the sheets look brand new.
The hotel is in a short walk distance to the Hermannplatz subway station, from which it's a matter of minutes to get to Unter den Linden and any other location in the city center. The Tegel airport is on the same subway line (U7).
Good for single business travellers, students, young couples, and basically for anybody who prefers to save on a hotel. Not good for the one who prefers comport and the view of the Brandenburg Gate from the hotel's window (no, you won't see the gate).
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC