Simple...referrals. You refer people to companies and products...they purchase, you make a %. The benefit, you don't manage any (of the advertisers) overhead. You simply drive referrals.
Affiliate Program - An automated marketing program where a Web advertiser or merchant recruits webmasters to place the merchant's banner ads or buttons on their own Web site. Webmasters will receive a referral fee or commission from sales when the customer has clicked the affiliate link to get to the merchant's Web site Web site to perform the desired action, usually make a purchase or fill out a contact form. The most common types of affiliate programs include pay-per-click, pay-per-lead, and pay-per-sale.