Ordered mine from the Book Depository. Thought I'd try them as my daughter uses them quite a lot.

BAW:
I think Jack has a tendency to hyperbole, but from what I have heard elsewhere, Amazon are not the best of employers. However their UK operation is bound by UK law so have to pay at least minimum wages and otherwise conform to minimum employment standards. Also a lot of stuff from Amazon actually comes from third parties who use Amazon as a "shop front", so it's worth checking who the stuff is actually coming from.