Sebastian's apartment was conveniently located near Ostkreutz station, which has a direct train to Schoenefeld airport and is near to the city centre by S-bahn. There are many cheap eateries near his apartment. The room was very clean, spacious and comfortable with enough privacy. It was a pity that my friend and I could not stay in Berlin for long to experience this great city. Even though we did not interact much with Sebastian, he was a great host and I highly recommend his apartment if you are ever visiting Berlin :)