A couple of years ago this was a real money making opportunity. I routinely bought the latest Apple iProducts in the US and sold my old ones for the same price I had paid new. Then, the blue dollar appeared. That changed everything as prices became out of reach for most Argentines (without cuotas), and those with the money simply went to Miami to buy what they wanted.
Craigslist is full of scammers and there are countless stories about getting paid in counterfeit bills. MercadoLibre is a difficult sell. You need to have a good rating, and even then you'll get countless messages asking for a lower price or if you want to trade for a Nokia cell phone.

I have an iPad2 and iPhone 4 that I do not use but have not yet been bothered to even get listed yet!