Buy underpriced used books. Outfit a phone with an ISBN reading app, scan the ISBN numbers of books at used bookstores and thrift shops, and compare the asking prices with what the books are selling for on a site like Amazon. Whenever you get a good hit (which won’t be often but, since the process is fast, won’t take long, either), buy the book and resell it online. Be discreet about this, as the store managers probably won’t like what you’re doing.
Try affiliate marketing. This means promoting someone else’s products or services for pay without actually carrying an inventory. There are many ways of incorporating affiliate marketing into your website/blog/page including banner ads (which are generally ineffective, as people tend to avoid these), linked articles (which are quite successful when the article content is thoughtful and doesn’t appear spammy), and product-placement videos (which can be very successful when done by people with charisma or a good sense of humor). You can even become an affiliate marketer without a website. Basic ways of making money through of affiliate marketing include:
Websites like Survey Junkie will pay you a decent chunk of change for the low-maintenance, borderline mindless task of completing surveys. Companies want to understand consumers better, and one way they do that is by compensating survey-takers (a.k.a. you). Most surveys pay between $0.50 and $1.25, and many of them take less than 5 minutes to do. You can read our full Survey Junkie review for more info.