Ebay works. Yes it isn't cheap but it is hard to sell something secondhand any other way.
Ebay also have very good SEO and they pay google a lot of money for the ranking, IOW they pay to expose your advert.
Otherwise, nothing stops you knocking up a website and stick a page on it entitled "For Sale" and see what happens. I can tell you... nothing will happen
I've been running a couple of websites; one for 20 years and one for 8 years and both have excellent SEO, but it took all those years, and above all a lot of relevant and verbose content.
The main thing to watch, IME, is stupid people buying something which they then don't want, or they thought it was something else. Paypal (mandatory for Ebay in the UK, at least) gives people 45 days to change their mind. And the world is full of truly stupid people
So one needs to do
- very good photos, showing the entire item close-up
- a very good and honest description; not the usual Ebay one which is often illiterate and way too brief
- a clear statement of what is included ("you will get what is shown in the photos")
- reference reviews (ebay no longer allows URLs so tell people what to google)
- not sell junk
IOW, make it hard for stupid people to buy the item, and if they do, cover yourself so a Not As Described claim is likely to fail. Paypal are bast*rds anyway and protect mostly the buyer...
If selling IT gear (cameras etc) sell them FAST and as soon as you bought the replacement; if you sit on stuff like that for a year, it will fetch much less
I've had some problems but only a few, out of many hundreds of items sold.
BTW I had a curious one the other day: a buyer who bought a £200+ item, but has zero feedback and joined Ebay the same day. "Obviously" a fraud, but apparently Ebay now allows "guest" buyers and that is how they appear. Time will tell...