Decluttr lets you sell everything from books to CDS to DVDs to electronics and even LEGO! It's my best recommendation for decluttering (hence the name!) by selling stuff you no longer want or need. With books, you just enter in the barcode or ISBN and they'll give you a value. It takes minutes to find out how much your stuff is worth and you don't have to register or anything to price things.
Set up a roadside stand. Depending on where you live, you could profit handsomely by setting up a roadside stand. If you live near a resort area, for example, you could buy cases of bottled water, put them on ice, and sell them to passers by for twice what you paid. Selling fruit and produce you grow yourself is also a smart idea in highly-traveled areas.
If you’re looking for inspiration, my friend Michelle Schroeder-Gardner of the website Making Sense of Sense has become the expert on all things affiliate marketing. Michelle earns more than $100,000 per month from her blog and the bulk of her income comes from affiliate sales. Michelle has had so much success with affiliate marketing that she even has her own course called Making Sense of Affiliate Marketing.