You can sell your ebooks through Amazon's Kindle program or Apple's iTunes Connect, which gives you access to a large majority of the digital-book reading market and the barriers for entry are incredibly low. You don't need to invest lots of money to make this happen, but you do need to invest lots of time, not only in writing the ebooks, but in marketing them as well.
Two-tier programs exist in the minority of affiliate programs; most are simply one-tier. Referral programs beyond two-tier resemble multi-level marketing (MLM) or network marketing but are different: Multi-level marketing (MLM) or network marketing associations tend to have more complex commission requirements/qualifications than standard affiliate programs.
No one knows your hometown like you do, and you can translate that into cash by leading tours of your city. The website vayable.com allows you to set up and guide tours around a particular cultural experience. If you’re the foremost expert on ghost stories, beer, architecture, or crime (or anything else!) in your town, then you can start leading tours for people who want to hear your stories.
Start a photography business and sell your photos online. If you have a nice DSLR camera and take good photos, do photography sessions or take photos of events, like parties and weddings. As another option, create fine art photos that people may want to hang on their walls, or take stock photos to sell online on sites like iStock Photo, Shutterstock, or Alamy.