1.Acquire USD through black market (at higher rate) (FEE loss #1)
2.Deposit USD to VirWox through CC or Paypal (FEE loss #2)
3.In VirWox: USD > Linden dollars (FEE loss #3)
4.In VirWox: Linden dollars > BTC (FEE loss #4)
5.Withdraw BTC from VirWox (FEE loss #5)
Why on Earth should you go such a complex way?
You can use localbitcoins much easier (paying directly with pesos), and even if you don't, I'm pretty sure there are many easier methods (though of course less easy than here).
The localbitcoins issue and other (darker) alternatives:
Ideally, local exchangers should be the way BUT remember we have a black market dollar. Thus we have an official dollar rate 1 usd = 5~ pesos and a "blue dollar" (black market) rate of 1usd = 8-9~ pesos.
Local sellers are obviously selling at blue dollar prices, so that makes it really really costly (borderline scammy).
If one could find an open heart altruist btc magnate to sell at official rate, that's jackpot.
A second more realistic scenario, is based on money exchange arbitrage and not a btc thing itself, but it's possible and it is being done, a lot.
In such a scenario I can buy stuff for you on the internet at a (new) credit card dollar rate (official rate + 25%, this is forced by gov' on visa, master, etc.), and you give me btc. Now I've got some BTC and I can hoard and hope for the future; or I could try and do some arbitrage selling in black market, but of course if acquiring btc was hard, imagine how hard it will be to get some liquid USD from my btc, to go and sell in BM.
I have recently found a loophole, where I get a web debit card (mastercard) with a valid ACH, to which I should withdraw my BTC to USD exchange. I then must buy a plane ticket, travel abroad, go to an ATM, withdraw my USD, smuggle them back in and sell in black market.
Of course, after all of these hassles, fees, travel costs, and the inherent criminality of it all.... gains are minimal to non-existant. Risk is uber-high.
EDIT: Realistically, the overall best investment for anyone here (or elsewhere) would actually be to start large scale ASIC mining farm, given we are paying 1/8 the electricity costs. But you would have to be very very very lucky to a) get an avalon unit (at it's official price, not the 10-20x resell price they are going for) and b) smuggle them from the US to Arg.