You don't need a large budget to create these additional income streams. Many of the Associate programs are free. A number of programs pay you a set percentage of total sales. What also makes these programs so nice is that they take care of the ordering process, credit cards processing, shipment and customer service. So all you have to do is get potential buyers to the sites.
Most programs pay monthly, some quarterly.
My philosophy is this. If I can relate a particular Associate program product or service to my site in some way, what do I have to lose.