Here are my favorite and am sure they'll help get you to that next level
[ame="http://www.amazon.com/gp/product/B0043RSCU6/ref=s9_simh_gw_p351_d4_i2?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=09F6P38SA6K9TV25KZQG&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846"]Kill Everyone: Advanced Strategies for No-Limit Hold 'Em Poker Tournaments and Sit-n-Gos: Lee Nelson, Tysen Streib: Amazon.com: Kindle Store[/ame]
This ones under $8 and one of my all time favorites and is mainly for MTT
[ame="http://www.amazon.com/Decide-Play-Great-Poker-ebook/dp/B0054DQNGI/ref=tmm_kin_title_0?ie=UTF8&qid=1359651825&sr=8-1"]Decide to Play Great Poker: A Strategy Guide to No-Limit Texas Hold Em: John Vorhaus, Annie Duke: Amazon.com: Kindle Store[/ame]
This one is also under 8 bucks and is for everything poker most likely have to read this more than once due to all the info they packed in here and this one would be the one that has helped my game more than any book