Wowio's a free e-book distributor. They find sponsors who get an ad in the front page of the PDF-format e-book. You can download up to 5 e-books per day. A bunch of comics are available. Most (all?) of them suck.
Starship Troopers the comic? Vomit.
Sore Thumbs? "Look! We have boobs!" Also, it's a webcomic, you can go back and read the archives if you want. The ebook editions were a sufficient anti-recommendation to me.
Lullaby? I liked Fables. I figured I might like this. But I haven't been motivated enough to read the rest of the ones I downloaded. The writing's not so good, although Alice managed to find a flamingo that serves as a kick-ass weapon.
Winning at Poker: Essential Hints and Tips by Dave Scharf. Gave up very early.
They have a bunch of public domain works available, but why would I download them there rather than from Project Gutenberg? You can also download some Kurt Vonnegut.