Six Sacred Swords is currently the Audible Daily Deal, meaning it’s discounted to $3.99 on the US Audible store. This sale may not be reflected in all regions, unfortunately.
If you’re not already familiar with Six Sacred Swords, this book takes place just after the War of Broken Mirrors. It also includes a frame story that takes place after On the Shoulders of Titans, so it’s a great book to jump into while you’re waiting for the third Arcane Ascension book.
If you’re interested, you can find it here: