I moved in with a Brazilian family, a professor and her husband(pictured above left at the cheese stand). Every Sunday they go to the local vegetable fair and buy a weeks' worth of fruits and veggies! There are many types of fairs in here in Goiania: Feira do Sol, Feira do Lua, Feira Hippie and so on. You can find anything from clothes, shoes, pets, vegetables, crafts, or necessary household items like pots and pans depending on which fair you go to. They normally have a designated day of the week. They have produce sections in grocery stores, but it is a lesser quality and not worth the cut in price for most items.
Haggling/bargaining with vendors is not very common, maybe at the end of the day (which for vegetable fairs is around 11 am, 7am people get the best picks) when produce is not as fresh. They normally have a set price per kilo or per quantity (for example: 6 ears of corn, 1R$). You put it in the basket or bowl and they weigh it ,bag it, and you pay.
Generally at fairs , no matter clothes fair or a vegetables one, there are some standard snack stands. I would say the most common street vendor foods from what i noticed are sweets stands, coco water/juice, pastei and popsicles. Today I tried a new one, sugar cane juice with lime(just under 2 R$)!
