These free to enter competitions close fairly soon …
This one from Servicescape is for a short story on any theme. The prize is $1,000.
This one offers a kickstart for novelists. The prize is £1,000 to help kickstart your writing, as well as advice and feedback.
Here’s another novel writing competition with a £1,000 prize.
The A Story For Daniel competition asks for up to 500 words with a joyful or uplifting theme. The prize is £100.
The Society of Authors are behind this novel writing competition which has a £4,000 prize.