—Você quer a sua via?
—Não, obrigado! Menos lixo...
Your credit/debit card transaction may have just cost you a lot more than you thought —R$90, R$990, or more; a friend was scammed for nearly R$5000 in SP.
The person brings the machine to your face showing the amount you owe, all you need to do is to enter your number and be quickly on your way. Sometimes the tiny screen may show a zero to the left, but you do not worry because, after all, a zero to the left adds nothing to the total. But what you don't know is that it is a common new scam that has taken in a few friends... especially targeting foreigners. Unscrupulous scammers, among them taxi drivers and others will add a 9; 99; or 990 ahead of the number and add spaces at the end so the screen only shows the amount you expect to pay (at least once I noticed a discrepancy, thinking nothing of it). You enter your PIN, politely thank the attendant, and drive/walk away none the wiser.
Without that little piece of paper, you would just throw away to look at, you have no idea you have just been taken. Such a nice attendant.
Solution: Always yes "Sim" when asked "Você quer a sua via?" This act in itself reduces the likelihood of an altered amount. Of course, always look to compare once the transaction is done.