There are some chancers (bandits) out there and he's one of them 😂😂😂😂😂
I think a lot of the prices are higher than what we might think reasonable due to the fact that some people are lazy and just try ebay.
A number of years ago when I had my Commando I was looking for some pieces, and did look on ebay. There was a certain, well known, dealer in Norton parts had exactly the part I was looking for but it was used and in a bit of a state, I then checked his shops' website and found the same part NEW for less than the heap of a part he had on ebay. Obviously chancing his arm, but there is a good chance someone would buy it without checking other avenues for the part.
As long as people accept daft prices these people will charge them, I understand some parts may be difficult to get but have a good look about before paying high prices.