Well, if you want to sell off your old stuff rather than setting up a product store, there is a method available.
Search for a GroupThere are several buying and selling groups on facebook. Best way to find is using the Search field in facebook. Pay attention to a group that is limited to your state , or more preferably your immediate location. Use search field with the words "sell" along with your geographical location. Check whether the results you get are actually groups or 3rd party sites.
Join the GroupMany of the groups are not open. You may need to ask for permission.
Read the RulesCheck the rules of the group/s you joined. You can access rules under Notes tab. These will include how to post items and how to deal with the buyers among others.
Post your itemDecide on a Test item and list it on the group. You will begin getting comments from prospective buyers. Make sure to interact with the comments. If you do not feel like selling to a particular person, dont be compelled.
Follow upOnce you have an agreement to sell, try sticking to it. Make sure the transactions are in cash. Accepting cheque or other means would not be advisable.
Live....and Let Live!