the whole bank system here in Argentina is a real shit because of a lot of goverment laws. But I don't think that the ATM fees is a result of any goverment stuff because the fee exist in Paraguay too.
The ATM fees here in Argentina had take effect since September 2009 on all cash machines and the fee is for every transaction and will increase your costs.
With any Credit or Debit card (like VISA, MC, Amex, ...) you don't need to pay this fee. I have a VISA and the fee (worldwide) will be every time 4% of the cashed amount and not for every transaction. Only my bank will cash me $3 if the 4% value is lower as that minimum fee.
About the problem that many people will only get out 300 Pesos I will declare why this will happend ...
The system behind all ATM (including VISA, etc.) will not work every time fine and have a lot of troubles of reading out the correct limit value. The standard limit of most cards is 300 in your currency if you are outside of your country.
Mostly the systems here in Argentina will read this limit and will give you the possibility to cash out 300 Pesos because they don't convert your currency
My experiance is that up to January 2008 I had never this problem on my VISA card. After this time I got every time (each transaction) as max. 300 Pesos. After increasing my limit through my bank to 600 I got every time 600 Pesos as max. per each transaction. At this moment I knowed that there is a currency change problem.
In beginning of 2009 some cash machines (best was Citybank or Galicia) giving me up to my real limit because they converted the limit in correct way. But all other banks hasn't done this.
Since beginning of this year I don't have seen that problem anymore and I will get on each cash machine my real limit. I think they have fixed - after 2 years of shit working - their systems in the background and I will hope that they will leave it as it is.
Otherwise with the ATM card from my ex-girlfriend it was in reverse mode. Before 2008 she had every time the problem to get the real amount. After 2008 she never had the problem to get the real amount in one transaction up to now (less of the additonal fee since Sept. 2009).
In Uruguay I never had any kind of this problem. As I know from a friend the ATM fee exist in Paraguay too but much time longer as here in Argentina. With VISA there isn't any additional fee their.
bye alex