AppCenter: The Pay-What-You-Want App Store Enabling indie developers to easily distribute native, Open Source apps for elementary OS https://www.indiegogo.com/projects/appcenter-the-pay-what-you-want-app-store#/
About the new concept of AppCenter: https://medium.com/elementaryos/building-the-future-of-elementary-os-9df3fa940b67#.gzrhajp55