I'm from Barbados in the Caribbean, but I'm currently spending the next few months living in Recife, Brazil. In Barbados the food prices are pretty alright, but some imported items can be pretty pricey. I often compare the prices of things here in Brazil to prices back home in Barbados.
Some things are very affordable - you can get a six pack of yogurt cups for R$2,50 which is like $1.25 US. I love chicken nuggets, so I buy a box of fifteen-twenty pieces for around R$4 ($2 US). the basics like bread, rice, spaghetti etc are all very low priced.
Yet, I've seen a simple tin of tuna cost almost R$6 - 8! Most of the brands in the supermarkets here are local, and some of the imported North American and European brands can be pretty expensive.
Fruits and veggies here are affordable in the supermarket, but I hear they're even cheaper from the street vendors. I definitely have to try this and see if it's true!