To earn with hubpages, you need to have Google AdSense account. If you are already using AdSense, you can configure it with your hubpages account. If you don't have AdSense you can apply through hubpages. But before you apply, make sure you have enough content. I had published ten hubs, and my hubs had been viewed 1000 times before I applied to AdSense.
Once your AdSense is approved, you have double chance of earning, one through hubpages earning program, another from AdSense.
You can also earn from amazon and ebay. But to earn from these programs, the visitor must buy the products visible on your page.