I've published puzzles for years under my Punzhu Puzzles title, and have recently published a fiction novel on Smashwords.
My blog has free puzzle magazines, and I use Smashwords for publishing puzzle ebooks for sale. "4-letter words" is an ebook with 320 puzzles and is available for $0.99 at Smashwoods, Apple iBook, Barnes and Noble, and other affiliates.
I've just published my first novel, Final Decree, on Smashwords and sold a copy the first day. I wasn't expecting a sale so quickly.