Some of the Forgotten Realms books are available, and one of them was even
offered as a freebie last year.
I think your best purchasing bet would be to get the books at Kobo using coupons when Kobo offers them (you might want to subscribe to
this thread in the Kobo forum which helpfully tracks the coupon deals if you haven't already).
Wizards of the Coast seems to be a non-Agency publisher which allows additional vendor/buyer discounts and here's the
20-page listing of what shows up for their catalogue, with most titles under $6, at least in Canada.