No matter how good your marketing skills are, you’ll make less money on a bad product than you will on a valuable one. Take the time to study the demand for a product before promoting it. Make sure to research the seller with care before teaming up. Your time is worth a lot, and you want to be sure you’re spending it on a product that is profitable and a seller you can believe in.
The second (and cheaper) path assumes that you have the design and dev chops yourself to build your dream software. Naturally, it’ll take more time to get your product off the ground, but being able to bootstrap the development of your software lets you retain more ownership in your business and be more in control of your path, making this a lower-cost, but higher time investment to make money selling apps.
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.