With 250 EUR a week you can perfectly live in Buenos Aires with local standards, which are not very different from European standards that you can find in Lisbon, Madrid or Rome.

At current rate 1000 Euros = 5,500 Argentine pesos

Is more than enough for a single to comfortably live in Buenos Aires in a 2 bedrooms apt. in a nice area like Palermo or Caballito.

High-quality areas like Puerto Maderos or Las Cañitas are quite more expensive.

This values are taken into account for an Argentinian national, I understand that without local "help" on dealing with agency/land owner; prices will be given with a "foreigner mark-up"