A number of multi-level pyramid type schemes exist which pay you to view ads. They are called "Paid To Click" or PTC sites. Some will pay as much as 2 cents per ad view. Others are a scam. Using a referral system so that other people's clicks ad to your earnings and diligently viewing about 5 ads a day has topped up my account and sure it is not much but it all ads up !
The one I've used is one of the most established, is definitely not a scam and genuinely does pay out.
