I've had a quick play with the postage calculator this morning and was also happy with the postage. I noticed there's a couple of sweet spots so as long as you keep the weight just under them it's pretty good.
My daughter's 7 and just the right age for me to read the Hobbit to. I'll let her see all the films when all 3 are done. However, I think exposing her to the books before the films is the best way to introduce her to Tolkien.