The DriveThruRPG printing and shipping looks like it could have been explained clearer. Here's how it works:
1) You back at a certain level.
2) Once the books are ready to be printed, you'll get a code (or 5 codes for the Gilded Company tier).
3) You then use that code to get a book printed, paying only the printing cost and shipping.
**If you back at Monster level and above, you don't need to worry about this - I'll take care of it for you.**
Estimated total cost for Scavenger tier (softback + PDFs) is £12 pledge + £3.90 printing + £3.78 shipping (to UK) = £19.68, or about $30.20 shipping to the US.
Estimated total cost for Sentinel tier (hardback + PDFs) is £16 pledge + £6.90 printing + £4.41 = £27.31, or about $42 shipping to the US.