There have no extra commission fee to sell ebook at Clickbank, only one-time $49.95 product activation fee. More details at below link: http://www.clickbank.com/sell_products.html?locale=EN
How do these vendors even make money then as most vendors offer a 75% commission that would mean that for a 50$ product he would get 50 -((0.5 * 75 + 7.5 * 0.5) + 1) = 7.25$!! That means that the vendor only gets 14,5% of the initial sale. Someone please tell me I'm wrong.
Not exactly true. $50 - ($1 + ($50 * 0.075) = $45.25 Affiliate gets $45.25 * 0.75 = $33.94 Vendor gets $45.25 * 0.25 = $11.31
Ahh ok, so apparently Clickbank gets his commission first before it gets divided between the vendor and the affiliate.