Entangled has put pretty much their entire Indulgence line on sale. I'm not sure how long it's going to last, but most of their titles (150 or more) are $0.99. They also have box sets with three or more books also on sale for $0.99. All of their books are in the 150-250 page range, so category length.
The most notable bargain I saw was the
Men of the Zodiac Box Set which is just $0.99 and includes the 12 short novels in the series, all by different authors.