As I've posted before, try El Marisol in Puerto Madero for a great steak and good price. Nice setting along the river, not a dive but upscale restaurant and probably only a $5.00 taxi ride. Last time we were 2 years ago there a meal for 2 with empenadas, salad, Bife de Chorizo (Like a NY strip) and a bottle of wine cost about $25.00. We'll be there again on Grand Prix.
Jim