We decided to sleep in a hostel in Varsovia because the hotels were very expensive. El Hostel seemed a good option since they not only offer dorms, but also double rooms with private bathroom. It was a great deal! You can reach the hostel with tram (only 3 stops from the center) and the place is cosy and VERY CLEAN. Our double room was in fact bigger than expected (we had a double bed, a single bed and a sofa) and the bathroom has been recently renewed and it was also great. They also offer you towels and free breakfast, so it was a pretty good decision!