Temporary rents are allowed by the "Rental law of Argentinian Nation" for people who lives more than 400 km (248 miles) from the place for a maximum time of 6 months.
As this rents don´t have a guarantor; you are asked to leave a security deposit thats usually the same amount as a month. This money is returned upon check out as long as you return the apartment in the same conditions as it was given.
You sign an agreement; between the owner and yourself accepting all the terms; there are usually standard agreements; but its always recomended to read them if you are not familiar with the intermediary agency.
You can find temporary rental agreements on the web.
But, how to choose and agency?
Recomendations are always the best way. I recomend you to take a look at how many properties they handle; the time they take to answer to your request; they way they treat you and if on there web site they have published the terms and conditions.
There a lot of reliable agents and there some that porteños call "Chantas"; this are people who try to take advantage or that will not provide the services they promise; this doesn´t aply to all; but you have to be cautious.
Most agencies charge an average of 20%, thats included in the price. They can ask for a few more dolars (30-50U$D) for administrative fees and late/early check in.
5 tips to avoid "Chantas" brokers:
1- Watch their web site, their ethic and professionalism
2- see if they have many properties, many properties means that a lot of owner trust them.
3- See how they answer your request
4-There should always be a land line phone number were to call.
5- Make sure that all the charges are included in the agreement and ask tehm if there are any extra charges
We have a company called yes-apartments.com but there are a lot in the market that you can be useful.