Sorry to come back to the discussion of the quantity of rooms available and the
cost of those rooms. Let me take the opportunity to suggest AirBnB as an
alternative if people are still seeking rooms and do not mind not being in a
hotel. In BA, for example, there are over 200 available based on criteria I set
(turn off Super Host and it is >300), starting at US$42 - see
https://www.airbnb.com/s/Buenos-Aires--Autonomous-City-of-Buenos-Aires--Argentina?checkin=04%2F03%2F2016&checkout=04%2F09%2F2016&room_types%5B%5D=Entire+home%2Fapt&superhost=true&zoom=13&search_by_map=true&sw_lat=-34.66012283057721&sw_lng=-58.456201399327824&ne_lat=-34.518665453754764&ne_lng=-58.300847853185246&ss_id=626eamgr.
While YMMV I and my colleagues have had some success with this for business
travel. Of course it means walking to the venue (or a taxi) but then I think
that is a chance to enjoy the local culture and see how people in another
country live.
- Jason