I have no idea at all what graphic designers earn here...at ALL, so please take what I say with a grain of salt.
That said, I do have perhaps a very GENERAL idea of what a normal salary might be. A low level office job which does not require terribly many qualifications may earn you roughly 2000 pesos per month. Maybe more maybe less, with inflation these things are hard to say.
A qualified professional in business, IT, programming, etc might earn around 4000 pesos per month.
Teachers in public secondary schools apparently earn starting from around 1400 pesos a month, to possibly quite a bit more with seniority. Anyone ever teach in a private school care to comment?
Non-professionals like waiters and cashiers have a really hard time I believe. I've seen advertisements for waiting tables offering to pay 50 pesos plus tips per 8 hour shift (and tipping is very, VERY light here...think maybe 1 or 2 pesos as a typical Argentine's tip)
Again, I really am nobody to say what people really earn, it'd be interesting to have an anonymous poll to see what expats are earning (counting only those who are actually employed in Argentina, of course, to not skew the numbers with those earning in American dollars or euros).
But what I do know is that you will definitely be making less than half of what someone makes in the US. Perhaps one third, or possibly one fourth... Bs As is a VERY expensive city for those who earn locally in pesos.