The current in Argentina is 220-240v, 50 Hz, AC. However, you can buy a transformer for your battery-charger or mobile here in Argentina for no more than U$S 50.

When using a transformer also take into account the watts that the item consumes.  For example:  the converter that you used for a mini-blowdryer (50 watts) will sizzle if used for a curling iron (125 watts).  You are risking the converter, the appliance itself, the wall outlet and the fusebox.  Not to mention that sparks may fly and start an electrical fire.

Also take into account that until a couple of years ago all plugs had rounded prongs. Now Argentina has standardised on type I sockets and plugs. Type C plugs and power points are still commonly found in older buildings (older hotel may have the old system in the bathroom and the newer grounded system in the bedroom).