Personally I got maybe 5 cents off an ebay sale from someone who signed up with my tracker. I never had luck with ebay in the days of olde with our own accounts linked and no hubpages ad program integration. I do however know many hubbers make more then $50 a month with ebay, and some make more then $500 a month with ebay in there hubs. (From forum posts and old discussions)
I say heck, give it a try if you can get an account and it all set up! There is nothing wrong with trying and if your successful you get something for it - imagine that!