You have to remember that in order to make money from Google Adsense, someone has to click on the Google Adsense ads surrounding your Hub article.
That cannot be YOU or you'll violate Adsense's Terms of Service. You can get your Google Account banned that way. That's called click fraud, and yes, Google is smart enough to know who did it. They track IP addresses.
You're not even allowed to encourage people to click on your ads either. People have gotten in trouble for that.
Why is Google so strict about it? Advertiser complaints. Gotta please the advertisers.
Now, when someone clicks on the Adsense ads surrounding your article, Google will first share the revenue with Hubpages, then Hubpages splits the revenue with you.
If you had your own blog, and you put your own Adsense ID onto it, Google would split the money directly with you.
In the past, they never revealed how much that was, but as of May 2010, they revealed that you get 68% of contextual ad revenue while they take the rest. This is per click, not per view. Of course, things constantly change.
If you want to earn "per view", then you'll want to write for Triond. They pay every month via PayPal, check or Western Union Money Transfer.
Of course, you'll need lots of views, in the thousands, before you start to see the $20 or $48 a month articles. So write lots of articles, or get your articles a lot of page views.
Contextual Adsense ads like you see on Hubpages work on a per click basis, not per view. On my Squidoo Lens based on a fitness DVD, I earned $7 once in clicks.
So try writing your hubs around weight loss or commercial-type products.