Try it.The best way is to go here...
http://appshopper.com/
On the top, click on iPad, All, and Free. Easiest way to see all the free apps.
You might want to change the Popular filter to All (just right of the category dropdown).Try it.
Lists 18 games for free on iPad. There's over 800 games, surely more than 18 are free lol. At least iTunes lists the top 50.
The first book I downloaded was The Divine Comedy because I've always wanted to read it and I knew it would be free. There are some really good free books on ibooks.I actually downloaded about 50 free iBooks last night also... if you search for "free" in the iBook Library hundreds if not thousands of free books appear for you to download. Mostly classics- Alice in Wonderland, Treasure Island, Time Machine, Art of War, Pygmalion, that sort of thing...