Looks to be an all time low of bananagrams with previous lowest being $15 over a year ago? The Nile do have it for slightly cheaper for $14.66(thenile.com.au), but postage will be an extra $5.99, so better at Amazon if you have prime!
It is also sold and delivered on Amazon by Shark games for $12.99 delivered). Credit to @bmaca, but they are a new seller without feedback so buy at own risk