Top 3 buy open source projects

京东抢购助手：包含登录，查询商品库存/价格，添加/清空购物车，抢购商品(下单)，查询订单等功能

An android eCommerce application for students through which they can buy and sell used goods .

([Swift] https://github.com/chenxing640/DYFStore) A lightweight and easy-to-use iOS library for In-App Purchases (Objective-C). DYFStoreKit uses blocks and notifications to wrap StoreKit, provides receipt verification and transaction persistence and doesn't require any external dependencies.