I've bought one cookbook for the Kindle - Rose's Heavenly Cakes, as well as downloading the first chapters of a few cookbooks. I looked at them on the Kindle itself and on the iPad version and was a bit disappointed, to be honest. The layout suffers on the Kindle, and it takes several pages to read even a modest recipe, so I found I was going back and forth several times any time I was reading a recipe. The Kindle software on the iPad is better, as it has a larger screen, but even there it was a bit cramped. Illustrations and tables also didn't show up very well.
In addition, searching is a problem - search results are not organized by recipe, just by individual words, so it's almost useless. At least you can click on the Table of Contents at any time and get a list of the recipes which will take you there when you click on their titles.
In general, I found the Kindle itself to be rather poor for cookbooks. The iPad is better, and the best is using a cooking app (or website) on the iPad. For example, the Epicurious app is excellent, and free, and there are some well reviewed cooking apps also, which are laid out for searching, for easy reviewing while you cook, and often have photos and videos attached.
Free ethnic cookbooks. Go to Shop in Kindle Store, then top sellers, then top sellers free. I find the best selection of the types of book I like free on the weekends. On holiday weekends they seem to have even better material. I am not familiar with these books, but they looked fun to try for free - Mexican, Polish, German, Israeli, Scottish-Irish, Gypsy, Burmese, and Indian.
OK, so if you search in the Kindle store on Hippocrene cookbook you will come up with more cookbooks most of which are free. This includes ones that do not make the top 100 downloaded list.
I do enjoy reading some cookbooks on my Kindle Fire--but mostly use Kindle when I climb into bed...each night...for an hour (or two). I'm totally in love with my Kindle, the light in it...makes for great bedtime reading. I like cookbooks on it that are the types with lots of info. I find that I will read things that normally I would not have time or inclination. For instance, I recently read everything I never wanted to know about CHOCOLATE...I found myself absorbed in it. So, what I'm trying to say is: details within cookbooks are fun to read on Kindle. (I'm one of those people who swore I'd never have a need for a Kindle...and now...especially because of the ability to increase the font and to have that backlighting...I am totally hooked on putting some cookbooks on Kindle. (But I also keep them in Kindle for PC...or Calibre...both free.)