Here are a few links to pages, blogs, communities and writers which offer writing advice for free:
General
Randy Ingermanson’s Snowflake Method
He explains his way of writing a novel, you can get free newsletter about advanced fiction writing and a free email-course about “how to publish a book”
BBC Writersroom
Tips on writing and the possibility to send in unsolicited scripts for films, shows ect
Writing fiction on about.com now The Balance
everything from finding a space to write to how to get published
Writers Digest
We all know that one I suppose
DiplomaGuide.com
A list of courses for free for aspiring writers and poets
Daily Writing Tips
on Twitter #hashtags for writers