The last volume in the IVP dictionary series, the Dictionary of the Old Testament: Prophets is now on sale for up to 60% off ($24) at the Westminster Bookstore if you buy two or more. Single copies are at 50% off ($30). If you spend at least $49 you also qualify for free postage.
The other volumes in the Old Testament and New Testament series are also on sale at 50% off. Go here for the OT and here for the NT..