I would suggest these books in order of importance in my opinion:
Principles of Foundation Engineering 5th Edition
by Braja M. Das (I believe this is a must have, I believe you can find a good used one for $45-75)
Civil Engineering Reference Manual (CERM)
By Michael Lindeburg ( I used the 8th Edition, If I had to do it over I would splurge for a new one, it is must have for the breath & depth even though the geo part is limited)
Six Minute Solutions for Geotechnical
(Most of the problems can be solved using Das and Lindeburg's CERM)
NCEES Civil Engineering Sample Exam 2008 edition (A must have)
Principles of Geotechnical Engineering 5th Edition
by Braja M. Das (Covers some basics the Principles Of Foundation Engineering doesn't, I bought mine used for $35 from Barnes and Noble)
Kaplan Civil Engineering Sample Exam 3rd edition 2008
(some different questions to work. I thought it was worth the price)
Soil Mechanics and Foundation Design: 201 Solved Problems
By Liiban Affi (It really isn't 201 questions as some were 5-6 part questions, he uses Terzhagi for foundations, a little different then the way CERM solves shallow foundation problems, but it was good practice, the expalnations al that detailed)
I also had a older Traffic & Highway Engineering text by Garber . It was helpful for some breath questions as well as some geotechnical questions such as heaving, asphalt, and some other obcure questions.
I also used an old book Statics and Strength of Materials 3rd Edition 1975
By Jensen and Chenoweth (for me this was helpful for the morning structural)
On the test in the afternoon I used the CERM, Das' Foundation Engineering, and the Traffic & Highway Engineering mostly. I passed.
i hope this helps.
