I got Vine's Complete Expository Dictionary of Old and New Testament Words for $2.48 (originally $24.79; $19.99 at Amazon) and Knowing God by J I Packer for $1.29 (originally $12.89; $11.44 at Amazon).
I might try for the other codes, but it's hard figuring out what to get. A good portion of my current wishlist is made up of Agency books (which will not be bought anytime soon), and Kobo has very few of the non-Agency ones.
Now, what can top this for a great start to the weekend? Maybe cupcakes?