for free: 免费的
Why do people work for free?
为什么人们会免费工作？
But he offers this advice for free.
不过这次扎基免费给出了以下建议

a bunch of: 一串.一群
Starting a bunch of office rumors?
开始一段办公室恋情的流言?
Is it because they were successful at hiring a bunch of people who had strong leadership attributes?
是因为他们成功地雇佣了一群具有强劲领导力的人吗？