You can click on the link on someone else's article but most programs, such as Google adsense, dislike - sometimes to the point of banning as far as Google goes - if you click on a link that is in your own article. On on your own blog, website, etc. They feel you are just gaming the system.
I did that a long time ago (10 years or so) - clicked on google links on a golf blog I had at the time - and got warning letters from Google about it. Same thing if you encourage people to click Adsense links. They do not like it at all.
I would imagine that Ebay would be the same since they pay for clicks. If you click on links in your own article they will probably be upset.
Instead use the links from someone else's article to go shopping.
That's my experience.