If you ask people will either say sell through Ebay or become an affiliate marketer. Either one can be a good choice if you're looking for income stream working from the comfort of your own home.
Ebay is straightforward enough. You sell through auction stuff you don't want but is still in good shape to people who may want what you have.
Affiliate marketing on the other hand is all about promoting a merchant's products or services and getting commission is someone buys using your affiliate link. The merchant will typically supply promotional materials and you just focus on promotion.