YSK: If you can't afford to pay for mindfulness apps like Headspace or Calm, you can find *free*, evidence-based mental health and mindfulness apps that were developed by researchers at the US Department of Veterans Affairs for use by civilians and veterans alike.
from /r/YouShouldKnow
YSK：如果你付不起Headspace或Calm这样的心智应用，你可以找到*免费的、基于证据的心理健康和心智应用，这些应用是由美国退伍军人事务部的研究人员开发的，供平民和退伍军人使用。