Sites like Share-A-Sale and Amplifinity provide referral fees. Vendors set the referral fees they're willing to pay and for what services. When the transaction happens, you get paid by the company for introducing a new customer to them. uRefer also allows merchants to set up referral programs for introductions and meetings, in addition to any transactions made.
The reality in affiliate marketing is that it's like most other work-at-home ventures; there are a few who are filthy rich, a good number who are successful enough to meet their goals, and a ton who aren't making anything. So, the question isn't really whether or not affiliate marketing is a viable income option (it is), but whether or not you can make affiliate marketing work for you. Only you can decide that. But to help, here are some tips.
28. Subscription – If you think of something valuable (newsletter, online magazine, etc.) that you can consistently offer on a certain basis (weekly, monthly, etc.), you may want to offer a subscription service. This could be a fee charged each time your product is sent out or on a monthly basis. Either way, this has to be something that your customers can only get by subscribing to your website.

If my piece of content is so unique and valuable around hiking backpack recommendations, that other reputable outdoor websites are willing to link to it and build the page’s authority, then I’d have a very real opportunity to rank high in organic search for these search terms (meaning, my page will come up first when someone searches for hiking backpacks).