I ordered from christianbook.com, getting free shipping with a code (you can ask for one over the phone for orders over $50). I made sure to buy the Standards Edition, which apparently has extra stuff compared to the U.S. Edition (and still has English units alongside the metric system, if that matters).
I ordered the homeschooler's guides (similar to the teacher's guide but without specific teaching strategies for large groups), workbooks, and textbooks. If I had to do it again, I might skip the workbooks, as we haven't used them at all so far.
