Of course you can use the likes of eBay or Amazon, but they usually have fees for selling. You can now also easily buy, sell or trade your 360 cameras on facebook and the best thing there are no fees and you can post for free. You might get lucky and pick up a real bargain.
To improve reliability of transactions, it relies on a couple of mechanisms:
First, buyers and sellers use their Facebook profile to post. The other party can then look at the profile and see if they are legitimate (e.g. if they belong to 360 camera groups, and what types of posts they’ve made). Disposable accounts don’t get approval to post.
Second, buyers and sellers are encouraged to post feedback. By reviewing the list of past transactions, you can see if the buyer or seller is a trustworthy resource.