Sometimes I shop at large retailers such as Walmart or Carrefour. Although I haven’t seen any hard facts to back up my assertions I will share what I believe to be most large retailers basic strategy. They sell some products below cost to get you in the door so that they can therefore sell most of their other products at a profit. This is referred to as a loss leader pricing strategy. I think their strategy centers around the fact that most people just do not have the time or the inclination to check prices and shop around.
I buy my dairy products at Carrefour on Mondays – “Lacteos Lunes” – where they give customers a coupon for a 30% discount on their next visit. It is the best deal on dairy that I have found in Buenos Aires so far.