transaction fees and product view questions

I just added Cartfly to my website hosted by Ning. I have two questions. I know that Cartfly charges a 3% transaction fee for every purchase but does Amazon also charge me to process the transaction? In other words, am I getting charged twice or just from Cartfly?

My second question is, is there a way to set the arrangement of my products to show all of them? Right now, the default seems to be that the products are stacked one on top of the other and I am afraid people will not know to use the arrow or click on the images behind the top one. I don't see anyplace in my settings to change the view permanently.