It turns out that as might be expected Kobo US has been running an Independence Day sale, which is still good through July 6th just before midnight EST.
Lots of trad-publisher stuff on promo mostly at the $1.99-$4.99 USD price point, with some books also discounted in other regions as well. Selection isn't quite as good as the still-ongoing Canada Day sale, but some interesting-looking books, especially in the non-fiction section, and many of them are couponable.