@danieladragan: Hello, there are free books at:
Librivox
Loyal Books
For purchasing high quality readings, we pay $14.95/mth for Audible
The monthly fee is most worth it and the narrations more consistent.
For other children’s tales, you can’t go wrong with Jim Weiss, which can be bought and selected by age, too, from Peace Hill Press: https://welltrainedmind.com/store/
Timeline of his readings: http://www.jimweiss.com/timeline-of-stories-and-tales/
If you get the Peace Hill Press newsletter, you get advertisements of their discounts on audios; that’s how I downloaded two Weiss productions for under $6.
At Amazon you can get some great deals on used (Very Good or Like New) CDs from Jim Weiss.
Lastly, Homeschoolradioshows sells huge collections of MP3 recordings of radio shows. They have three collections: each at $89, so you’d have to save up, but the collections are awesome! They are here:
Living Books for the Ears
American History
Old Fashioned Holiday
I hope that gives you a start. What I have usually done is listened to a sample from the free one as well as from Audible and then made my choice as to what I download for free versus what I use an Audible credit on.