Being an Amazon affiliate is one of the ways to make money through Hubpages and their payout is only when somebody buys anything from Amazon, after being re-directed from your hub.
There are other revenue earning possibilities in Hubpages - through Google, eBay and Hubpages own Ad program.
You get paid for clicks (when somebody clicks on the ad displayed in your Hub) and also for impressions (when somebody just reads your hub).
Get registered with all the third party affiliates. Write lots and lots of quality hubs based on your expertise and interest.
Go through all the FAQ's and introductory documents on understanding the revenue earning opportunities through HP.