I am buying a PH (sort of semi-detached little house) near Parque Chacabuco, after looking for about 6 months around CABA. As with all real estate, price very much depends a lot on location. We wanted to spend no more than $200K all up and needed at least 2br plus terraza, so fairly quickly focused on Caballito and Parque Chacabuco.
One issue that I had not understood before starting the process concerns money, specifically bank accounts. To the best of my knowledge, without a DNI you can´t open a bank account in Argentina. I know, no-one wants a bank account here but, without one, it is a bit difficult to get a house buying sum of money into the country. I mean, you can do it, but it is a pain in the a-s, involving bank account in Uruguay or various other manoevres. When the purchase goes through, you need to be able to justify where your money came from - I don´t know if the AFIP bothers much with foreigners but this is a legal requirement and the escribano should mention it. They write down the sale a fair bit (ie they write a lower price in the legal documentation) but there is also the government valuation of the property (the VIR), which sets a sort of lower limit on the price.
The easiest way to avoid these hassles is to buy from an expat or other person with a $ bank account overseas. In that case, the $ never come into the country - problem largely solved! However, the average Argentine in the street doesn´t have a foreign bank account (even in Uruguay). That puts you in the expat/expensive end of the market, but if you want to live in Palermo and those areas, it doesn´t matter - that´s where the expats live!
The other thing you need to do is to register yourself with the AFIP. I forget what that particular registration is called, but you need it in order to be a property owner. Again, the escribano should mention that.
We finished up paying US$135,000 for a 114 m2 with 2 1/2 br, patio and terraza and a brilliant quincho. [But it needs some work..!]
Final comment: I have owned flats or houses in many countries. Apart from the hassles with the $, which are an aggravation, the process is no worse here than some countries and probably better than many (eg Italy). Make sure you get a decent escribano..maybe get a recommendation from someone...
Good luck!