It happened to me many times---cashiers making mistakes (deliberate or not) in punching the calculator and give you the wrong figure. I would usually borrow their calculator and punch the numbers myself and end up with the right amount to be paid which is way less than what the cashier said. Oftentimes, shortchanging happens even in big supermarkets, drive-thrus(when you are in a hurry) etc. One time I was supposed to receive 45o php for my change. The cashier loudly counted the money and loudly proclaimed the amount 45o. Others would have left right away but I counted the change in front of her and, voila, it was 100 php short! So I told the lady, "How come you counted 450 when this is only 350----lacking 100! " She of course apologized and gave me the correct amount. And countless of other instances----it is rampant. Count your change/money before leaving the counter.