post, you'll find quite a few suggestions. Enjoy!
Update: This deal is no longer available, but there is one free title for Kindle as of today (7/31/14) called The Black Moth. It is interesting to me that Heyer's books are so expensive. There must be quite a demand for them. I see that with Amazon Unlimited (which I don't have), you can read many Heyer titles for free. Here are a few I saw that are only $2.99: Bath Tangle and April Lady. Unfortunately, the one I've heard the most rave reviews about Civil Contract is almost ten dollars.
(In case you are interested, The Black Moth has been put into audio form by Julie at Forgotten Classics.)