I certainly do n ot want to give the impression that ebay is a n-go area.
Although I have been stung twice as a seller, that is across 20 year! It was only for small amounts not for expensive items where I take extra precautions before shipping.
I have been shafted by legit high-street sellers more than I have been buying on ebay.
If something has arrived damaged or not as described I have just contacted the seller and in each time it was either replaced (if they had more stock) or I received a partial refund that was to my satisfaction.
So ebay is definitely a good place to sell (especially when they send to a £1 final sales fee offer!)...just do what you would do when selling on here..get the money first, check the address that you are sending to.
Hopefully, when buying anything from a retail shop...one would ask questions to make sure that it is what you want and also up to the spec that you would expect.
As to Paypal.
I have had multiple paypal accounts for many years and have never had a problem (oh great now I've said it...).
If you are careless with your passwords or details etc it is just like being careless with your bank details or having your address with your keys etc.
Paypal is not the problem, it is how some folk are a little, shall we say , careless with what they do online.....
That is why I do not give many personal details to this and other forums, facebook, twitter, messanger etc etc and I have 'alter-ego' email accounts in different names to act as a firewall for stuff that is not personal and might bring spam, phishing, malware etc.