What will be the cheapest way to get several cartons of book from London to America?

Question

My wife and I have been living in London, England, for two years. We arrived with only two suitcases each, but we have acquired lots of books (which we need for our work) while here.

What is the cheapest way to get several cartons of books --- our only household effects other than clothes --- back to the U.S.?

Answer 1

UPS or FedEx