Here is an offer from Storybundle:

http://storybundle.com/

Pay as little as $3 for four steampunk books (move the slider) OR Pay $10 and unlock 3 bonus books. So... 4 for $3 or 7 for $10.

Check out via Amazon. Paypal or credit card. I used Amazon.
Download includes both mobi and epub files.

Books rate around 4 stars at goodreads, with numerous reviews.

I picked up this bundle one or two weeks ago, I'm about 20 pages into Black Mercury and it's looking good.