If you have a Coinbase and GDAX account, you can make Bitcoin, Ethereum, and Litecoin transactions without paying any fee.
You simply click Deposit on GDAX, and transfer over the funds you want to send from your Coinbase account. After that you click Withdraw on GDAX and choose to withdraw to the Bitcoin/Ethereum/Litecoin address that you want to make a payment to.
This is nice when you are making smaller transactions and you don't want to bother with high fees (BTC I'm looking at you).