I have been to countries like Japan where cash is the preferred way of payment. Here in the United States, it is very common to use a credit card. What about Brazil? Is it common to use credit cards like Visa to pay for your purchases at stores and restaurants, etc? Or should one bring cash instead?
In bigger cities like São Paulo or touristic places like Foz do Iguaçu or Ouro Preto cards are accepted virtually everywhere - even in food stands on the street (I even saw once people selling brownies with marijuana and accepting credit cards). I've also never seen any minimum amount limit for card payments and it's normal to pay with a card even for chewing gum. Mastercard and Visa are always accepted, I'm not sure about other types. If you go to national parks or rural areas it may happen they won't accept credit cards, but it's rare unless you go to some remote places.
I always have around R$100 with me for emergencies but I have to use cash not more often then once every few weeks. Also, most ATMs are closed at night, so it's wise to have at least some cash with you.
Also, they will always ask if you want to pay as "credito" or "debito", which obviously means credit or debit card, from my experience 90% of foreign cards should be always treated as "credito", no matter what type they are in the issuing country.
Be sure to inform your bank that you're going to Brazil, it's quite common that banks treat this country as "risky" so they block your card when you use it here for the first time (happened to me several times and other foreigners I met here).
Users in comments mentioned they had major issues when using foreign cards, so it might be worth to take more money with you, but I think (hope) it's rather an exception than a common occurence.