A few months ago I mentioned a free to enter (obviously) 100 word competition. The prize was publication of the story in a free e-anthology for 20 semi-finalists, feedback from Curtis Brown for the best three of those and a Curtis Brown novel writing course for the winner. I, and around 1,000 others, had a go and I'm one of the semi finalists.
You can get your free copy here. (If you don't have a kobo you can download a free app and read it on your computer)
Prima were running a writing competition with a kobo as a prize (I was the March winner). They're now running one with £100 on offer for the best short story. Send your 800 words to email@example.com
I also entered several competitions I've come nowhere in, but I'm keeping tactfully quiet about those.