I use coinbase, trust me i have my bad days with this site, but all is good now,
Coinbase to buy bitcoins only. Gdax belongs to coinbase, if you have a coinbase account, use your same info to log into gdax, from there pull your bitcoins from coinbase to gdax, its only like $1.00 for feese. from gdax you can now transfer your bitcoins to an exchange like Binance is what i use. the best to buy coins with the lowest fees.

its free to sign up, this is were im holding 6 different types of cryptocurrency untill i get my ledger nano s then i will transfer them and hold them for the next 20yrs
sign up here at binance
https://www.binance.com/?ref=15923065