There are many free resources online for eBooks and audiobooks.  Try some of these, and if you have more suggestions, add them in the comments.

 

Southview’s MackinVIA
For eBooks & audiobooks

Ankeny Kirkendall Library Bridges
Requires library card

Project Gutenberg
Great for the classics

Open Library
1000+ libraries banded together to make books available

RIVETED BY SIMON TEEN 
Free contemporary Young Adult (YA) books offered every month

sync
Summer program that makes two great YA audiobooks available every week from May-August every year – sign up for a text or email reminder