WritersDigest.com and WritingForward.com both websites that provide hundreds of free writing prompts. ThinkWritten.com is another website that offers free writing prompts. Writers can also create prompts on their own or ask other writers for ideas.
Writing prompts are a great tool for writers who may need an idea for a story or for those who want to explore topics that they wouldn't ordinarily think up on their own. Prompts are often used in writing classes as practice exercises.
Poets & Writers' website, PW.org, offers writing prompts designed for writers of fiction, creative nonfiction, and poetry. LanguageIsAVirus.com features an automatic writing prompt generated for writers who find themselves in need of inspiration. Users can also submit their own prompts to the site for others to use. Ask other writers for prompts. They may have a great idea that they couldn't bring to life themselves.
The National Writing Project suggests writers create their own writing prompts by imagining scenarios that might occur in their everyday lives, or by responding to a situation in their favorite work of fiction. They also suggest writing about a real life event that happened to the writer, but imagining it from the perspective of another person in the story. Writing prompts that are drawn from the writer's personal experience can sometimes lead to better writing than a random prompt taken from a website.