welcome Kris, to MobileRead.
You are going to love love love your K.
First, we have lots of free books available here. Check the table under "e-books" You can sort by genre, author or title.
You want the mobipocket format.
Second, did you know, you can use your local public library's e-books on your Kindle? You just need to download the books to your laptop, run kindlefix.py and you can upload them to the K. They will expire after the loan date so , no harm no foul. Click on my linkys for the step by step guide, and ask questions when you need to.
There are also more free books at
www.feedbooks.com
Realize all the free books are copyright free, which means most are from 'ancient' times, to you Im sure, but you'll find a lot of classic, well written stories.
Enjoy the site and learn!