Mina asked:
 >Just curious, how do you find all these :)  However you do it, I'm grateful.

The link at the bottom of the e-mails shows all that are free that 
day. I buy all of the free ones. I then can check each that are free 
that day and Amazon will tell me at the top if I have bought it 
before. If not, then I announce.

I also have a spreadsheet in descending date order where I record 
each Kindle-only book as it comes out. To get the books to add to 
that, I use this link, which has all the paleo books in descending 
publication date order.

<http://www.amazon.com/s/search-alias=books&keywords=paleo&sort=daterank>http://www.amazon.com/s/search-alias=books&keywords=paleo&sort=daterank 


Now this also includes new hard cover books. So I click Kindle. Then 
I scroll past all the books that haven't been published yet.

In the spreadsheet I have columns for name, ASIN, status (e.g. 
withdrawn), and notes. I note if it went free. This mainly shows that 
given enough time more than 3/4 of these books were free at some point.

To ease the creation of the e-mail, I have a spreadsheet macro. By 
pressing Ctrl-U it reads the ASIN from Column B and creates the link 
that I then paste into the e-mail. The book name and author I copy 
from Column A.

Don.