The Betrayal of the Duchess: The Scandal That Unmade the Bourbon Monarchy and Made France Modern by Maurice Samuels is on sale at Kindle for $4.99 which might not seem cheap, but it’s a 75% discount off the regular price of $19.99. And it gets a 50¢ Great on Kindle credit while existing ones will knock down the price a bit more.
It’s an account of the Duchesse de Berry’s attempt to restore the Bourbon monarchy and of antisemitism in 19th century France as well. I found it both fascinating and illuminating and I highly recommend it.