Shipping books (media) vs ground advantage

[stlcard]

I have been selling mostly ball cards.  I am starting to sell books.  What should I do - if anyrhing - to change shipping charges - media for books vs ground advantage for cards???  I have a flat rate shipping for cards of 3.63 for no matter how many cards.  Obviously that would not do for, say, 3 or 4 books - or even 1 maybe.  Anyway I need some help from one with experience.  

[shipscript]

I would refer you to the shipping forum and the selling forum so that you can get advice from a larger group of sellers:

https://community.ebay.com/t5/Shipping/bd-p/shipping-returns-db 

https://community.ebay.com/t5/Selling/bd-p/selling-db