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.
User-friendly App: Decluttr is a mobile-ready platform made for selling on the go. The mobile app is a great help when you’re hunched over miscellaneous boxes in your dank basement or sweltering attic. You can use the app to scan in your items directly and utilize Decluttr’s “valuation engine” to quickly and easily see exactly how much you can earn. Many popular online selling platforms, including eBay and Amazon, are designed first and foremost with desktop and laptop users in mind.