I have an amazon.com credit card, which is now part of Chase. I applied for the card at amazon.com and immediately got $30 to spend at amazon.com. I don't know if this is still available or even if you can still apply for the card right at the amazon.com site. But I just checked the Chase site and here are the rewards:
* Earn 3 points on eligible Amazon.com purchases
* Earn 2 points on eligible gas, dining, and drugstore purchases
* Earn 1 point on purchases everywhere else
Reward redemptions start at 2,500 points.
When I first got the card, the only reward was a coupon for $25 for 2500 points, redeemable only at amazon.com. This was fine with me because I use my credit card for almost everything and I made a lot of purchases at amazon.com, making my points add up quickly. More recently, I've been making fewer amazon.com purchases, so I'm happy that they've added a cash reward - a $50 check for 5000 points - as well as a number of other rewards (
https://www.choosemyrewards.com/Media/C-AmazonConsumer.pdf).
You can also check out
http://www.creditcards.com/, one of the sites that sorts cards by category - rewards, cash back, low interest, etc. - and provides the benefits and requirements for each card. The site also lets you compare cards.