After years of those cheap shipping rates, I've had to raise them as things have gotten more expensive. Only a slight increase but sorry about the hassle. They are still pretty cheap and it is a flat rate so the more you get, it doesn't cost more.
The new rates are calculated by paypal and are listed on the bookstore:
$3 standard and $7 expedited.
Canada is $5
United Kingdom is $12
International is $15