Besides the use of affiliate programs the only other way i can think of is surveys. You can sign up for tons of free legit surveys that will actually pay. The only problem is it is a very slow progress and you only get a few surveys a month. Most legit surveys offer you points for each survey and as you collect points you can eventually turn those points in for cash or gift certificates, electronics, etc. I signed up for surveys and do them when I get them. In about 6 months ill start to see some income but its not a lot and it takes awhile. Surveys are a way for a little extra money but take forever before you see even a little profit. Hope this helps