Handy tip- if you're buying funds on Coinbase and intending to send them, Coinbase will charge you a fee. You can get around this by:

1. Sending funds from your Coinbase account into GDAX (same login).
2. In GDAX, transfer your coins to the address you want to move it.

GDAX charges no fees for transfers (unless they've changed it in the last month), so essentially it's free.

Also, if you're a US citizen that can transfer money via your bank into GDAX, you can avoid the Coinbase fees by putting in a limit order via GDAX instead of Coinbase. There is still a small fee on GDAX, but much better than Coinbase. Consider this if you're purchasing often as you'll save a decent amount in the long run!