My 10-year-old son brought home a book from our park’s free library box. It was a biology textbook – teachers edition. He said it looked interesting and hey, it was free (having no idea you could sell it). I scanned it in my Amazon seller app and realized it was worth around $150. He was so excited. We listed it for sale for $130 and it sold! Going to tell him, he just made $130!
However, like anything else truly worthwhile, apps require a significant investment of your time or money upfront. If you don't have the skills, then you have to hire someone who can assist you in creating a great app. But first you need to come up with an idea that will sell. Do the proper market research and analytics to come up with the right app.
17. Amazon – Have you heard of FBA? It stands for “Fulfilled by Amazon” and it’s getting pretty popular. Basically, you buy products (in bulk is best) and ship them to Amazon for them to store. When your products sell, Amazon packs them up, ships them out and sends you the money (after taking their cut). There are people making a full-time living from FBA, while others just do it for some extra money. https://incomeforeverybody.tumblr.com/