Merriam-Webster has released the The Official SCRABBLE® Players Dictionary, Fifth Edition. Although they list it for $25.95, Amazon currently has it at $6.83. I plan to purchase one soon.
NASPA, the North American SCRABBLE Players Association, has the The Official Tournament and Club Word List, 2014 Edition for $22 until Aug 13, then it goes up to $24.95. However, you have to be a member to purchase it, meaning it costs $30 more. Though, a trial membership should be good enough, which is a cheaper $15.
The difference between the two is twofold. One, the dictionary has been purged of offensive words whereas the full list has all words. Two, the dictionary includes definitions and other forms, whereas the list does not.
Getting the dictionary and printing up the delta might be the best option to all the word on the cheap, nice as an "official" version may be.
Speaking of lists, there are many. I have two and three letter word lists printed up, besides the 70% vowel list and a few bingo lists based on RETINA and the like. They are all grossly out of date, so i'll probably print up new ones when i'm sure they are using the new words. Last time i printed up two copies of everything except the longer three word list. My brother and i play with the lists and the dictionary available. It's just so much more fun that way.