Hotel or Apartment in Buenos Aires

I hear many people rent an apartment when they go to Buenos Aires, they find it more convenient and even cheaper. Is this possible and how? I want to stay 3 weeks and will probably cook in order to save money, so do you suggest renting an apartment or going to a hotel?

For those who stay longer, like you do, the better option is to get an apartment, since you will be able to cook freely and will have more room for yourself. Here are just some of the web sites you could use (being that there are like a thousand more on Internet):
www.living-like-locals.com; www.apartments.ba; www.buenosaireshabitat.com etc. ENJOY!