short change =少找钱

↓

I think I was shortchanged in the restaurant, because I've only got $10 in my wallet when I should have $20 .

我感觉饭店给我少找钱了，因为我钱包里只有10美元，本来应该有20的呀。

或者，可以说

not give someone enough change =少找钱

He did not give enough change, and people did not notice.

他没有找够钱，人们也没有注意到。

loose change =零钱、散钱

I have some loose change in my pocket. I'll use it to buy something in the vending machine.

我口袋里有些零钱，我准备拿去自动售货机上买些东西。

price difference =价差

There's always a big price difference between a new car and a used car.

新车和二手车的价格总是有很大的差别。