You will be more than fine on 16k USD a year here. I'm no expert, I have only been here for just over a month but you should be fine and actually be able to live beyond what I would deem ¨middle class¨ as far as some characteristics go, it just really depends what you prioritize on spending money on and what you cut back on and/or eliminate all-together.
For example, I knew I wanted to live in a good, safe, and central area, but because I am never home and use my place more as a crash pad (IE: bed, shower, place to chill), I opted for a basic shared flat in Recoleta, as opposed to a private ¨ex-pat¨ type of apartment that costs thousands per month and eats away at a huge chunk of money each month. It is still quite nice, I have a large bedroom with balcony, a pretty spacious double closet and cleaning service three times a week. This for me is perfect, and at this time I require nothing more. Some ex-pats might want the privacy of living alone, a gourmet kitchen with all the gadgets, designer furniture, etc, that they are used to back home.
In turn however, I do spend more than average on eating out, as I also do not cook at all and eat out practically all of the time, and manage to eat out very very well in top restaurants for very little. (Steak dinners that in the States might run me upwards of $150 a pop, here for around the equivalent of $28 USD and lunch menus at quality restaurants can cost the same as what you'd pay at McDonalds) I also go out to good boliches about 3 times a week.
I carefully assess everything I spend money on, I altogether eliminate buying things which I feel are ridiculously overpriced unless it is direly neccessary, and I opt for quality local products (shower gel, toothpaste, etc) as opposed to trusty old (but easily 6 times more expensive) american brands like Colgate. I am not referring to generic ¨off brand¨ products, just brands that because they are made in Argentina are considerably cheaper and I personally also prefer them, but am by no means living frugally or ¨being cheap¨, just being smart, and I really have a general feeling of living better than I would be able to live in both the States and in my native Spain here for a lesser dime.
It all depends on what is important to you in your lifestyle, I guess. Most of my Argentine friends earn between 3500-5000 per month and as you said, live decently.
