You can purchase USD-COIN from these places
Go to Binance
To provide users with more secure and convenient block-chain asset exchange services, polymerization of global high-quality block chain assets, is committed to creating a world-class block chain asset trading platform.
Go to Bitfinex
The largest and most advanced cryptocurrencies exchange
Go to Poloniex
Welcome to Poloniex. We are a US-based digital asset exchange offering maximum security and advanced trading features.
Go to HitBTC
The most advanced cryptocurrency exchange to buy and sell Bitcoin, Ethereum, Litecoin, Monero, ZCash, DigitalNote, Ardor.
Go to Korbit
Trade Bitcoin & Ethereum. Transfer money globally. Korbit, Korea's leading digital currency exchange.
Go to OkEx