As I picked up the last item, the thread organizer box, I mentioned the sale from the JoAnn's website to the sales associate, and she said that online sales are not always the same as in-store sales.
So, it turns out that I went around the store(for almost an hour) collecting everything from my list, just to have to leave all the stuff in the carrying basket.
I explained that I found all the stuff online on a 30% off sewing notions sale, and the sales associate told me that if I bring in a printout of the items on sale, that they'll match at least some of the sale items.
I tried buying the stuff online, but the website is apparently broken, so hopefully we'll be able to go sometime tomorrow.
I went on the site an hour or so ago, and almost nothing was still on sale, so I'm hoping that if we can go to JoAnn's tomorrow, and I show them the printout, they'll sell me the stuff at the sale prices.
Wish me luck!