Use this link to get your free Stellar https://coinbase.com/earn/xlm/invite/4f9m6xw2
I just did it and earned 10$ of XLM for answering a few questions!
After you finish the questions they give you a link like mine for friends to get free XLM, and when they complete the task we get $10 more of XLM, and up to $40 total!