1. Banks have different expectations for the future, which directly leads to different prices. 2. Banks charge different fees, and some banks charge relatively high fees. 3. The exchange rate is constantly changing, and this kind of uncertainty will happen.

Exchange rate, also known as foreign exchange rate, foreign exchange rate or foreign exchange market, refers to the ratio or price of one country's currency to another country's currency or the price of another country's currency expressed in one country's currency.