Check out the RIVER HOTEL located on 86 Montevideo. We stayed there from 7-9 May 2005 for US$42 per night for a standard room with a double bed. They have suites (a little larger, having a small sitting area) for about US$55.
The rate of US$42 for the River Hotel was actually negotiated in pesos, in person at the front desk of the hotel. It cost AR$120 pesos per night for a standard room and AR$160 pesos for a suite. At the time, the exchange rate came out to US$42 per night -- that includes taxes and the small continental breakfast every morning.
If you book via internet, it may cost a little bit more? -- we saw charges of US$40+21% tax as the lowest price on the web. We decided to just go to BA without any hotel reservations and check out the three hotels we had narrowed down and decide from there. It worked out fine ONLY because it is the low season, mid-week, and we were able to get a good price negotiating in person.
The reason we stayed there is because, after looking at several hotels' rooms, we found this one to be not only affordable and clean, but also having newer furniture and -- the most important of all -- soundproofing of the room. (The most important thing when searching for hotels, we found out, is to make sure the rooms have double-paned, soundproof windows.) Even some of the expensive hotels do not have this feature!
River Hotel features slick stone-tiled floors and granite sinks in the bath, and plenty of towels. The bathrooms are very small, but they are very clean, and as I described, they make up for the small size by using expensive fixtures and appointments. So it feels like one of the a 4-star hotels in BA, even though it's a 3-star. Rooms have cable TV and adequate storage space in the mirrored closets.
River Hotel includes a small buffet breakfast in the downstairs lobby area. It was nothing special, with large & small croissants, sliced bread (white and wheat), corn flakes, frosted flakes, milk, juice, yogurts, one type of sliced meat, and one type of sliced white cheese. There was also tea and coffee.
The lobby area is a kind of cafe during the day & evenings, and as such it is sometimes smoky with cigarettes, but that is inescapable wherever you go in Buenos Aires.
They have free internet access via a computer in what must have been formerly a telephone booth in the lobby (you can close the glass door for more privacy).
There is a workout room on the 8th floor with a bike, a treadmill, and weights, and a TV and air conditioning. It also has a shower, toilet, and a small sauna. They set up a balcony there with lounge chairs, but it's just one of those nice efforts that one would probably not use.
The staff speak English, though some speak it better than others. They are very friendly and were able to help us find nearby ice cream and steak shops.
Overall, the hotel, which is relatively new -- seems to have been built in 2001, is a terrific deal. The furniture is very modern and clean. For the price, this hotel is much better than older, more established hotels, which look nice from the lobby but are shabby in the rooms themselves.
From River Hotel you can walk to Teatro Colon (we went to the ballet of Sleeping Beauty -- $25 per person for side balcony seats) and to many restaurants including the BEST steak restaurant in Argentina, called Parrilla Pena, located on Rodriguez Pena street, between Viamonte and Tucuman. This was recommended to us by a nice Argentinian man, and we had our best meal there. We had one Bife de Lomo and one Bife de Chorizo Ancho, plus fantastic salad....
River Hotel is the best-kept secret in Buenos Aires.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.