Crossway Impact is a reward program from Crossway Books. There is a one time registration fee (but you choose what that fee is) and then you get 25% off of everything you buy from Crossway.org, flat rate $5 shipping on everything except case quantities) and exclusive monthly offers.
Yesterday Crossway added a new ebook benefit. If you purchase a paperback or hardcover of a book from Crossway, then you can also purchase the ebook version for 75% off.
One of the unique things about the Crossway Impact program is that 5% of all revenue from Impact members will be donated to fund the distribution of the Global Study Bible to ministries around the world.
The only problem with the program is that it only can be used at the time of purchase. So you cannot later decide to get an ebook or get ebooks for books you have already purchased.