A monitor showing incoming calls is hung on a wall at the customer's unit of on-line retailer Jumia in Lagos April 10, 2014. There are two main reasons people shop online: it's cheaper or they can't be bothered with a trip to the store. And in Lagos, a city of 21 million people, a trip to the store can kill your entire day if you lose the traffic lottery. Jumia has 100,000 Nigerian customer accounts and sales are increasing by 15 percent a month. REUTERS/Akintunde Akinleye (NIGERIA - Tags: SCIENCE TECHNOLOGY BUSINESS)