The "Full Color Edition" of
The NKJV Study Bible is on sale for $6.99.
B&N Amazon
If you have the plain ol' monochrome edition already, though, don't bother.
The print edition is very nice, but the ebook falls rather flat. There are a few pictures spread through the text, but the two editions otherwise only differ in some minor formatting details. If you're not sure, the free sample (at least at Barnes & Noble) includes Genesis, Exodus and Leviticus, so you can look for yourself.