You may have heard of the decentralized open source market place called Openbazaar, but probably have not tried it out. I only say this from my own experience after having a number of items listed for sale on the platform since the beginning of the year. I have not had a single nibble of interest from any buyers. This leads me to believe that there just are not enough people in the cryptocurrency sphere to enable a healthy marketplace to exist at this time. You are still much better off going to Amazon, eBay, Craigslist or Kijiji. I will continue to keep some items listed just to try and support the platform, but I do not expect that I will ever get a sale. Check out my store.
The concept of Openbazaar is great! Grab the software (see link at bottom of this post), start up an account and explore other peoples items for sale or put up some of your own. If you create a store with items, you will stay online as long as you keep the software running. If you stop running the software, your store will eventually disappear from the platform cache, so it is important to keep your software running if you want people to find your store. Nobody can shut down your account, store or ability to buy/sell. You may be unlisted from the official Openbazaar search (called OB1) if you or your items get flagged, but that only removes you from that search platform. You will still be visible on anybody else's search platform and anybody with the know-how can run one. In fact, there was a more popular search platform at one time but it appears to have disappeared and the community is waiting for someone to set up another uncensored one. At the moment it is a bit difficult to search for those questionable or blatantly illegal items, but they are there if you know where to look.
You can choose from Bitcoin, Bitcoin Cash, Litecoin or Zcash as a method of payment. There are no fees and you choose to use a moderator when buying/selling to avoid being scammed. A moderator basically holds payments in escrow until a purchased product has been received, at which point they will release the payment to finalize the transaction. Anybody can apply to be a moderator (and can choose if their service is free or has a fee). Moderators have to maintain a reputation score as well in hopes of weeding out the bad ones.
While Openbazaar already started in 2016 and are on a stable version 2 of their software, it is still far from being a good and complete experience. For example, useful tools for store owners are missing. There are no stats of any kind. You have no idea if anybody is even looking at your items or can find your store. Also, as mentioned before, there is a huge lack of third-party search engines.