The taxis that you get at AEP had the reputation for being the worst rip-off artists in the city. I don't know if this was fixed lately so beware. It's a very short ride to Recoleta. I suggest you get some advice from the driver who takes you from EZE to AEP or from the folks at the MTL desk. I don't know if you speak Spanish but the drivers are usually not fluent in English.