I pull in anywhere from $400-$600 in adsense off my blog, it's not exactly passive because I have to contribute content to it. But I originally only put AS on there to cover hosting costs (and other servers for dev, etc) but now it's starting to get closer to "income".

I'm still putting it into things like Raspberry Pis, Arduinos, Parallellas etc for stuff to write about on the blog. I use that money to try out other services as well, it's nowhere near what I'd call a "business" at this point.