Cafe Press: This website allows you to create digital designs that can then be sold on the platform. You'll earn a commission for everything that sells and you'll never have to deal with logistics like printing, warehousing and customer service. If you have some graphic design skills, then this is a great potential source for your web-based income.
Monetize a hobby. While some hobbies actually cost money, others can be transformed into a profitable business venture. Ultimately, it depends on what your hobby is and how talented you are. You could turn your love of photography, for example, into a part-time gig taking family portraits and wedding photos or selling prints on Etsy or at arts fairs.
An affiliate marketing program is a lot of work, and in most situations there's a lot of competition so you're not going to be bringing in money immediately. Business owners and entrepreneurs suppose that all you need do is setup a site and choose an affiliate to associate with and then just let it run its course. But according to Three Ladders Marketing, only 0.6% of affiliate marketers surveyed have been in the game since 2013. That means that affiliate marketing takes time and effort to build and make money.
You could also opt to use existing websites for making money. These include both active income and passive income methods. For example, you could sell some used items or invest in creating some digital designs that then can be sold on merchandise. Again, devote a sizable portion of your time to passive income so that you can slowly build up earnings that will arrive on autopilot without any extra added effort.