1. Never travel without a flashlight. These are good for walking at night and opening exterior doors on uneven, unlit streets; in blackouts; and importantly, when the electrical wiring fails on your house.
2. I did not cook lunch, I bought it. I was rice, beans, manioc flour, fish stew with palm oil and hot peppers, and salad. This cost $3, but you have to know what you are doing to find a lunch for such a low price.
3. The supermarket delivers your groceries on a bicycle.
4. Bus rides now cost as much as $1. Minimum wage is $265/month, and the work month is 220 hours.
5. When I first came here, bus rides cost half that or less, and the minimum wage was $50/month, or 20% of the current minimum wage.
6. This was why so many minimum wage workers could not ride buses. The figures in point (5) suggest things have improved.
7. This town is the 13th most expensive of 15 major cities. Here, one person needs $114 worth of groceries per month, at minimum, to live. It takes 107 hours to earn $114. So basic foods cost over a third of one’s minimum wage.
Axé.
coldhearted scientist وداد 
1 dozen eggs + 1 Juan Canary melon + 1 kg. bananas = 7 Brazilian R$ = 4 USD.
That was cheaper than the U.S., I think.
But when I bought beer, bottled juice, dish detergent, sterilized milk in one of those cardboard bricks, i.e. more industrialized food, prices were comparable to those in the U.S., I think.
Everything here that is in a supermarket is much more expensive than it would be if you can find it elsewhere, I think.
In Madrid I found that the rich suburban hypermarkets were much fancier and much cheaper than more urban supermarkets. I have not yet checked to see whether that is true here.