Now that we have a new thread and someone taking care of the OP it's probably worth having a section for these apps that deal seekers should own.
There's AppGratis and App of the Day which often feature limited time freebies. Unfortunately App of the Day is UK only, but the apk can be grabbed from here. The deals themselves work for anyone, and is usually in the form of the code "appoftheday" but it's nice to have it installed and wake up to a notification of a new freebie.
Then there's AppSales to be notified of price drops.
Thanks for the info about the App of the Day. I was wondering why I none of my devices were compatible with it. Being a UK only app explains it. Thanks for the apk.
In case anyone was wondering where I found those games that offer free Amazon Coins, it was via the Amazon Appstore on my Kindle Fire HD. There are ads in the store that mention the free coins offers. Back when those 23 free apps had 20 Amazon Coins ($4.60 free) there was an ad that listed all those apps. I was surprised it lasted for a week.
There is a currently an ad that mentions buying certain indie games and earning Amazon Coins, but it doesn't seem to be offering any coins at the moment. Maybe they haven't updated it yet.
On your Kindle go to apps -> Store. Sometimes you can go to the games section of the store and it will have ads for sales or other offers.
If I spot anything good I'll post it here.