To go back to the original question, I rely on Google, the Bartleby edition of Brewer's online and a �2 secondhand copy of something called the Wordsworth Dictionary of Phrase and Fable, based on Brewer's original and added to, pub c 2000.
On the whole, they work fine.
At Christmas, I gave up the unequal struggle to find a 'current' Brewer's in any of my local bookshops (temporarily out of print, I was told). And beware - there are many volumes that turn out to be 'Brewer's' dictionary of, er, modern or 20th/21st century phrase and fable. The original is long out of copyright, and thus it's perfectly possible to produce as many imitators as publishers care to.
My conclusion is - buy any old secondhand copy, as cheaply as possible, and rely on Google as a back-up.