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!
people who visited the site but did not opt in > you can use negative audiences for your ads with facebook ads, you just take visitors to the site and substract the people that visited the thank you page. For people who did not purchase, you simply can't with affiliate marketing unless the vendor adds a conversion pixel of yours on their thank you page.
Tools & Resources: I’ve written a pretty comprehensive guide on the best web design software that covers both free and premium software packages. If you’re serious about becoming a web designer, then I recommend purchasing the full Adobe Creative Cloud Suite. At $49.99 per month, this is probably a bargain considering what you can achieve with this set of tools.
If you have a good idea for an app, and the skills to create it, then producing your own premium app can be profitable. However, with so many free apps available, it may be hard to convince people to pay. If you want to go down the premium app route, consider having a basic free version to encourage people to download the app in the first place. You can then provide the option of upgrading to a premium plan once users realize how useful the app is.