(Affiliate links ahead)
The first two volumes of Frieren are free to read until the 19th. Might be interesting to people who want to catch up with the Frieren BBC offshoot. Same for the first 6 volumes of Detective Conan.
As for non-free stuff, there’s a sale from TO books going on until the 9th, so I’m afraid I have to pimp Ascendance of a Bookworm again. The first LN and the first manga volume for each arc (e.g. Arc 2) are on sale for 99 Yen, and all the rest are 30% off and have 50% coin bonus. This time, they included all the manga, the LN for Arcs 1-4 and the Junior Bunko version (same text but with furigana and more illustrations, but split into more volumes) of the LN in the sale.