compartodepto.com
I'll admit, I have not actually rented a room from here, but there are a lot of rooms listed across the quality/price spectrum. Seems like a good option.
Facebook page Buenos Aires Expat Hub . Go to their real estate page. Rooms in houses there. Mostly Palermo. Be careful of Craig s list. Rip off artists use it .
What I look for in a Private Room in Shared Apt,
Location . max 3 blocks either side of Av, Santa Fe From Callao to Scalabrini Ortiz , preferably Price Most rooms under US$20 per day are dismall - for Monthly Rental figure $6000 ARS minimum shared.
Private bath if Possible
Wifi fast
TV
Elevator
Aircon
If you must reserve with CC make sure its reputable
Referrals , may be fake
Only one shared room in Apt.
Good luck
Caution ; Returning late at night to Areas near Once Station, Congreso, Retiro, is safe only by Taxi...
Most shared rooms in Apts are Offered for students and for long periods perhaps 6 months. Retired or unemployed are not that welcome since they spend all day in the Room. Also when several rooms are rented in the same apt they look for a homogenous crowd... IMO