For my stay I had the Basic Room, 1 Bedroom (ROOM 301) for a little under $40 USD. My experience might be a little skewed/different than the average person because I actually was staying in Hongdae, left all of my belongings besides a backpack in Hongdae and so I would not have had safety concerns for my belongings that I would have "left behind," however I had the floor to myself to the best of my knowledge.
When I arrived, I noticed their was a sign that said to call to check-in which worried me since I had a "data-only" plan for my phone and I was travelling solo AND there didn't seem to be any person(s) on the inside. However I don't know how or why but I was able to call them and wasn't charged for roaming fees or anything. A cute older sounding couple answered and walked me through the door code and basic room info.
The room was basic and on the smaller side, however it did not feel small for me and my backpack only. It had a twin bunk bed with heating pads on each bed, the room had both an A/C unit as well as a heater unit. 301 was the room closest to the two shared restroom spaces as well as large mirror space for getting ready in the morning. I loved and utilized this space for getting ready for my Nami Island trip. The restrooms are the usual Korea toilet/ shower room combined into one and they had some shampoo and conditioner left there.
Although I did not use the bus out here the bus station was right outside and CU is right nearby as well. 8/10 would stay again.