Would it be worth spending money for a new phrase? The great thing about language is that it's free - unless you are paying for an English course at college, or buying a language learning course on CD, or even buying a book.  And even then, your investment cost is much less than the return that the new language knowledge brings. 

When it comes to phrases, nothing beats a great phrase at just the right moment in a conversation!  The value of having just the right thing to say is difficult to measure - could you put a price on it?