a friend or a cueva is going to be your best bet in this day and age, unfortunately. especially since officially you can only buy 200USD at the bank.
the bitcoin idea has been discussed before on here in other threads, you won't be able to open an account on one of the exchanges here as a foreigner (based on my last understanding and attempts to do so myself). there is localbitcoins exchange, where you can buy bitcoins from individuals, but you will be losing there too as the ARS/BTC rates are generally worse than the market value of BTC.