If you haven't checked out the previous Smashwords sales, it's probably worth taking a look at the threads for the two previous sales this year (links below). The authors who choose to put their works on sale each time are usually pretty much the same, and usually mostly the same titles too, so I've found seriously diminishing returns for scouring through the books on sale after you've done it a couple of times. (And totally agree on the horrible search engine...)
But if you haven't checked out the Smashwords sales before, luckily if you look at the last couple of threads, folks will have largely done the scouring through for you.
July 2017 sale thread:
https://www.mobileread.com/forums/sh...d.php?t=288225
March 2017 sale thread:
https://www.mobileread.com/forums/sh...d.php?t=284228
There are threads for the even older Smashwords sales too, but that diminishing returns thing...

If you really want them, you can search for and find the older threads too...