We described sites offering free ebooks in another article. Some of these resources also offer free audiobooks. There are also sites that specialize in free audiobooks. Free audiobooks are usually classic works that are now in the public domain.
LibriVox - LibriVox is home to many free audiobooks. The classic works are read and recorded by volunteers so you won't have to listen to a computer generated voice. There are thousands of titles available. They are available in MP3 downloads and iTunes formats. You can also listen to them online.
Loyal Books - Loyal Books offers free public domain audiobooks. There is a top 100 list and genre categories.
Open Culture - Open Culture lists hundreds of free audiobooks from authors including Aesop, Twain, Tolstoy, Hemingway and more.
Lit2Go - Lit2Go is a free online collection of stories and poems in Mp3 (audiobook) format
StoryNory - StoryNory offers free audio stories that include fairytales, classics, myths and more.
Archive.org - The Internet Archive has a large number of free audiobooks and poetry recordings.
ThoughtAudio - ThoughtAudio offers free audio books for a selection of classic literature and philosophy titles.
Free Audio Books YouTube Channel - This YouTube channel offers thousands of audiobook recordings.
Audiobook Subscription Services
There are also many audiobook subscription services. These are free for a short time period, usually 30 days. These types of services offer the free trial period before they begin charging a monthly fee, enabling potential subscribers to try out the service.
Audible - Audible from Amazon offers a 30-day free trial. Audible claims to have the biggest audiobook selection.
Audiobooks.com - Audiobooks has a 30 day trail period. They have over 100,000 audiobooks available.
Kobo Audiobooks- Kobo offers the first audiobook free general its free trial.
Scribd - Scribd is free for 30 days. Scribd then lets users listen to unlimited audiobooks for a monthly fee. The subscription also includes ebooks and other documents.