Sort:  

You typically have to have a verified bank account or credit card on file with them first. This means adding the account, then waiting a few days for CoinBase to make two small deposits to it, then coming back and telling CoinBase what the amounts were. THEN you can buy Bitcoin, Ethereum, and Litecoin on the site. :)

Patience, little grasshopper, patience. I am really bad at the whole waiting thing.