Shipping is really difficult to get right, particularly across international boundaries, when you also need to include the price of customs.

Here in Israel, personal imports under $75 are customs-free and VAT-free, and with Amazon US granting free shipping for orders over $49, I typically just bundle 2-3 books into the same order to get into the "magic" range, where the total price is cheaper than it is for most Americans in the US (no sales tax). I have a very difficult time believing any other site could beat that pricing.

Really interesting insight, currently the site doesn't support bundling with multiple book orders, but if I build multiple book bundling and the site knows your location and can calculate full costs from the booksite itself with that info, it should be able to help you find the cheapest application of the "magic" range. I'll see how quickly I can make that happen for you.