I got a late afternoon email from Early Bird Books (Open Road Media), advertising a number of mysteries on sale at $1.99, "for today only". Not sure why the email came so late in the day, or exactly whose today "today" is, but here is a list of the books, with Amazon US links. The email indicates that they are on sale at all the usual suspect ebook retailers, so if you want to try Kobo or BN or others, they probably will be on sale there too, but I don't have time to do multiple links/blurbs right now. Most have been on sale before, but YMMV...
Just Desserts, #1 in the Savannah Reid series by G. A. McKevett
link:
https://www.amazon.com/Just-Desserts.../dp/B00J90ELMU
Permed to Death, #1 in the Bad Hair Day series by Nancy J. Cohen
link:
https://www.amazon.com/Permed-Death-.../dp/B00KFU6QYY
Corpus de Crossword, #6 in the Crossword series by Nero Blanc
link:
https://www.amazon.com/Corpus-Crossw.../dp/B00N2CLU0C
Who Pays the Piper? is a title in the Ernest Lamb series by Patricia Wentworth. The blurb says it's the 2nd in the series but
SYKM doesn't list it - perhaps it has been re-issued with a different title, however,
SYKM says the second one is
Pursuit of a Parcel, and that title also is available from Open Road.

link:
https://www.amazon.com/Pays-Piper-Er.../dp/B01CTOTG5E
Madness in Maggody is the fifth in the Arly Hanks series by Joan Hess
link:
https://www.amazon.com/Madness-Maggo.../dp/B01ENRHK5I
Steamed is the first in the Gourmet Girl series by by Jessica Conant-Park and Susan Conant
link:
https://www.amazon.com/Steamed-Gourm.../dp/B016VNIGS2