As part of a 1-day special (July 16th) of discount Random House titles from both Kobo and Amazon (presumably elsewhere as well), several sfnal works are available for $1.99-$3.99 in Canada & the US.
This includes George R. R. Martin's
A Game of Thrones (the
iBooks Enhanced Edition which is supposed to have maps, notes, and other bonuses is also $1.99 (regularly something like $12 CAD or so), if you've been curious about exactly what these things contain), Andy Weir's
The Martian, and additional fantasy novels by newer authors Katherine Arden (likened to Naomi Novik's
Uprooted) and Brunonia Barry (likened to Deborah Harkness'
A Discovery of Witches).
Linkage for the sale @
Kobo CA (also works for the US, which doesn't seem to have a special promo banner up, once you swap the country code) and
Amazon main
Also, @ $2.99, it looks like Tor has put a bunch of their recent Hugo & Nebula nominee authors on sale across the usual retailers, with this year's finalist titles from Cixin Liu, Ada Palmer, Charlie Jane Anders, Fran Wilde (who was in Best Novelette and has a 1st-in-series novel here), etc. Linkage for the lot at
Kobo CA. There are a few other titles which are presumably the sporadically rotated Macmillan monthly specials, as well as some short stories and serials you'll have to weed out.