Sourcebook has their Georgette Heyer Regency Romances on sale for $2.99 at the usual retailers, although there are a few available at Amazon for less. At B&N, where it's a special of the day, there are 36 of them, so I am not going to list them all.
Amazon
Kobo (if the Kobo unlimited 50% off coupon 50READ still works, that makes them $1.50!)
B&N