Rip somebody off: to cheat somebody, by making them pay too much, by selling them something of poor quality, etc. 敲诈;讹诈

Tourists complain of being ripped off by local cab drivers.

游客们抱怨被当地的出租车司机敲了竹杠.

Soak: to obtain a lot of money from somebody by making them pay very high taxes or prices

向(某人)敲竹杠;宰(某人);向(某人)征收重税

He was accused of soaking his clients.

他被指控向客户敲竹杠.

Gouge: to force somebody to pay an unfairly high price for something; to raise prices unfairly 敲(某人)的竹杠;诈骗钱财;漫天要价

Price gouging is widespread.

漫天要价的情况普遍存在.

cost sb an arm and a leg:to cost sb a lot of money

(使)花一大笔钱

This ring cost me an arm and a leg.

我为这戒指花了一大笔钱.

Cost an arm and a leg表示"耗资不菲,付出过高代价",这仅仅是一个简单的比喻而已,用失去人体四肢中的"两肢"来比喻"付出昂贵代价".

overcharge: to make somebody pay too much for something

多收(某人的)钱 verb ~ (sb) (for sth)

Make sure they don’t overcharge you for the drinks. 注意别让他们多收饮料费.

We were overcharged by ￡5. 我们让人家多收了5 英镑.