Ojo though - it is often MORE expensive to buy in bulk than to buy multiple smaller packages at the stores like Makro. Makes sense - absolutely not. Happens - all the time. I go to Makro to do my shopping as it is considerably cheaper than Carrefour/Coto/etc. However, I often wind up buying multiples of something in smaller quantities rather than one larger package when shopping there. Always check the price per kilo or item. For example I bought diapers the other day. Buying in packs of 14, they were 1.06 pesos per diaper. The larger packs of diapers, each diaper cost 1.45 pesos. So cheaper to buy multiple smaller packs. Same with spices, etc.
The logic as it was explained to me by an Argentine was that if you could afford to buy in large quantities at once, you can afford to pay more. ??? Makes no sense but again, Argentina.
And of course if you want to deal with the headache, you can go to the central market. I believe there are also roving markets in each neighborhood. They sell food at low prices.