My 21 year old daughter and I visited Rio at the end of her semester abroad in Brazil. I found this apartment on Trip Advisor and booked it here. The apartment is on a main street with bus service and cabs right outside. The beaches are about a 15 minute walk. There is a doorman and elevator. We felt very safe.
The apartment is studio sized with one double bed. The shower took some getting used to as you have to light the gas to heat water but the pressure is good and a nice shower after a day at the beach is fine. The kitchen is tiny but we only used the refrigerator to keep drinks cold. There were clean sheets and towels.
There is no WIFI at the apartment but the mall across the street and most restaurants have it. There is an internet cord. The TV and fan worked well. We couldn't find a cork screw so you may want to pack your own.
If you are looking for affordable with just the basics. This is a good choice. Eve, the owner is very kind and kept in touch before, during, and after to ensure we had the key when we arrived and had a good experience.