$30 is quite a deal (Buy it now price) for these 3 excellent books. Too bad I have them all already!
Ozzies book is of course THE beginners guide to slack key and it is so good it's almost like having him there in the room with you.
The other texts are quite good and excellent for expanding your repertoire. I've learned several tunes from the Mark Hanson book as well.
I have the Keola Beamer / Mark Nelso book but have yet to start it. Still working on a lot of other stuff!
One word of caution---you may want to ask if the CD's for these books come with the book, as all 3 have CD's when origionally sold. It is much, much easier to learn the tunes with a CD to help you. THe Mark Hanson CD even slows the songs down for you, but the full song is NOT played at perfomance speed so thats a slight bummer.