A good way to make money online is trough sites that allow you to sell your used stuff.
Ebay is the most famous and known : an online auction and shopping website in which people and businesses buy and sell a large variety of goods and services worldwide.
In eBay you need to pay a listing fee in order to sell your items and this listing charge is not refundable (check out eBay fees).
However, getting started is quite easy, once you become familiar with listing methods, payments, shipments, etc.
And sell your used stuff that fill completely your basement is particularely interesting, above all when you realize that the system works.
Make a research of what the used item that you want to sell is valued around the web, then take a nice picture, where you clearly see all the details.
After this, provide a complete description, with indication of price and shipment details.
Consider that eBay is the site where you can find the most part of the buyers looking for business and eBay is very popular around the world.
All these auction sites do not charge listing fees, you pay only if you realize to sell your items.
The marketplace of Ebid, AtOncer or Craiglist is not so big as E-bay, but they are gaining popularity, as zero listing fee alternative.
Amazon is another possibility to consider in order to make money selling your used stuff.
Have fun selling your used items !