Startup Idea : Lets take control of our foreign exchange

ok so how many times have you come back from abroad with money still in your pocket or you're at the airport and wish you could take more money but don't want to be fleeced by the airport foreign exchange? Here's the solution and it stops those greedy exchange guys getting there slice of our money - letsxchange is an app similar in concept to Uber. Once registered you can 'request' a search for someone, like you, who wants to exchange currency. Here's an example of how it can work - you are at the airport waiting to fly home. You have $300 left and you use your letsxchange app. Someone in the airport is looking for dollars and gets your request. You meet up and swap money.