Does KDP Print charge different amounts for different trim sizes?
The cost of printing your book will depend on which country the book is being printed in and some of the settings related to how your book is printed. You can verify it directly with the sizes that you are thinking about using their Printing Cost and Royalty Calculator.
The price to ship from KDP Print is the same no matter the trim size. All that matters there is where you are shipping your books and is based on quantity. Click here for their shipping rates..