The original source for this deal seems to be Smashwords, where apparently it's deep-discounted as part of the Read an E-Book Week sale: direct linkage to the SW version of
Hollywood Headlines Mysteries Boxed Set (Books 1-3)
I moderately enjoyed
Spying in High Heels which I got as a freebie (still free @
Smashwords, by the way), and I'm sympathetic to Halliday over the Dorchester situation, even though I'm not too keen on her yanking existing series to KDP Select-ivize, which apparently kills re-downloading of purchased books in several stores.
I think I'll be picking up this one to show support for both the author and MultiFormat DRM-free sales via Smashwords (and I'll be very sure to back up multiple copies of my purchase in various locations, just in case), even though I have all the individual books from the KDP Select freebie-ization.