Cost really isn't a factor, but it's hard cover to $20 retail, -10% members discount at Barnes and Noble.
It's "Luke Skywalker and the Shadows of Mindor". Set 5.5 ABY, it's a divergence from the usual fair of Star Wars books and goes back to the early days of Splinter of the Minds Eye and the Han Solo and Lando Calrissian short novels back in the early 80s.