Cost per click was more common in the early days of affiliate marketing but has diminished in use over time due to click fraud issues very similar to the click fraud issues modern search engines are facing today. Contextual advertising programs are not considered in the statistic pertaining to the diminished use of cost per click, as it is uncertain if contextual advertising can be considered affiliate marketing.
Affiliate marketing is also called "performance marketing", in reference to how sales employees are typically being compensated. Such employees are typically paid a commission for each sale they close, and sometimes are paid performance incentives for exceeding objectives. Affiliates are not employed by the advertiser whose products or services they promote, but the compensation models applied to affiliate marketing are very similar to the ones used for people in the advertisers' internal sales department.
Being in Australia, I’m not required to do anything by the law (although I hear talk that there may be changes around this). I don’t disclose every single Amazon link on my photography blog in a direct way but do I have a disclaimer/disclosure page on the blog. When I’m doing a ‘best seller list’ always include a disclaimer on those posts as the whole page is filled with affiliate links. I have also written numerous times on DPS about how the links to Amazon earn us money and help the site to keep growing and be free.
It’s free to join the SellHealth affiliate program, though you do have to apply and be accepted before you can start promoting their products. Once you’re accepted, you’ll have access to a number of tools, graphics, banners and more that you can use to promote SellHealth products. The sales are actually made at company-owned Websites, which look professional and handle all of the selling. Commissions vary, but the base rate is 30% of all sales and upsells, and SellHealth says you can earn up to $350 per sale.