You can purchase ETHEREUM-POW-IOU from these places
Go to Kucoin.com
The People's Exchange
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 Kraken
Buy, sell and margin trade Bitcoin (BTC) and Etherum (ETH) in exchange with EUR, USD, CAD, GBP, and JPY.
Go to YoBit
Buy and sell Bitcoin (BTC) on YoBit Exchange!