What are some ways to make money online without spending any?

Sorry, didn't mean to make it sound like it's an easy peazy process, it isn't. It's a lot of hard work.

Re Adsense, I found it very easy. I joined as a member of HubPages and I can put my Adsense code on any site that meets Google's TOS.

Keeping up a blog or consistently writing for others (a site or clients) is a lot of work and commitment. But you can do it for no cost and make some money....over time, if you put in the effort.