I think the fee schedule links would be quite helpful.
There are other factors that need to be considered which may affect your profit like the type of listing format you will be using and the type of shipping service you will be offering your customers, so it's a bit difficult to say...
Also, you have to consider that even if you may make a better profit on one site (based on calculations) it may not necessarily be a hot product on that particular site. In the article shared by Irene, the writer said
Iâ€™m removing Ebay from seriously being in this comparison simply because you go to Half.com to buy textbooks, not Ebay. Ebay is for everything else and if you try to sell a textbook on Ebay, youâ€™ll most likely be sorely disappointed unless itâ€™s a collectible or something of that nature.
Another consideration is the type of customers that flock to the site. Many have always said that most items are sold at a much better price on Amazon compared to others (seller's perspective) because of the type of customers that go there.
I think what fudjj said in another thread is quite practical and may be something you should consider: Link hidden: Login to view
All the best! :)
PS Maybe you should try listing the same item in all 3 sites and see how it fares. If you do - do let us know how it went. Would be great to read about the actual experience. -Thanks :)