It's all about generating traffic, you could try and sell from your own platform if you could market it effectively.
You can always make use of the free listing sites, just watch out that their success fees don't strangle any profit you make in the event of you actually making a sale.
Bonanzle.com is one that has no listing fee and very inexpensive success fees, but as with most other sites, it doesn't carry the traffic volume of an Ebay or an Amazon.