I suffer from buying really cheap ebooks. It is a horrible addiction, but I console myself with the fact that it is quite environmentally friendly, my house will be in no danger of looking like a hoarder's domicile, and that I do not have to explain myself to my frowning wife unlike the mysterious packages full of lead that arrive via mail.
So, today, weak willed fella that I am, I bought:
An Invincible Beast: Understanding the Hellenistic Pike Phalanx in Action C$1.59 link
The Nisibis War: The Defence of the Roman East AD 337-363 C$1.16 link
A History of the Art of War in the Middle Ages C$1.91
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Battle-Cruisers: A History 1908-48 C$.99 link
The Great Siege: Malta 1565 C$1.99 link
And although it's not history, it is definitely historically exciting and inspiring, Kobo has a sale of all Bernard Cornwall's books. (Bought all the six books of "The Last Kingdom" for C$8.99!)
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All the links above are to Canadian websites and prices, but hopefully your home countries are also following suit. I did hear that simply changing your address in Amazon to, say, the CN Tower, allows you to buy books from your "new" home country, then switch your address back to your real one. Also, the Kobo bookstore sells epub formats, but hopefully everyone knows you can convert it to the Kindle .azw format, if you remove the DRM.