Fantastic fantasist Brandon Sanderson has two ebooks on sale: Infinity Blade: Awakening and Infinity Blade: Redemption.
I've read two of his novellas so far (not these yet)--both imaginative, potent works. One of which went on to win a Hugo.
Good prices (less than $5) on two massive and massively cool collections (not literally massive since they're ebooks, but they're full of energy which Einstein tells us is the same):
The Jack Vance Treasury
The Greatship by Robert Reed