Angel By My Side: The True Story of a Dog Who Saved a Man...and a Man Who Saved a Dog ($9.99 US), by Mike Lingenfelter , is free for UK Kindle customers tonight. (
UK link)
Book Description
In 1995, Mike Lingenfelter was ready for his life to be over. Two serious heart attacks and open-heart surgery had taken away most of the good things he had in his life. But then a golden retriever named Dakota, who had been rescued from death himself, came to help Mike with his rehabilitation recovery. This is the story of how Dakota became Mike's protector and best friend, saving Mike's life several times.
Just an FYI: this one is from Hay House, so it may not cross over for US customers as a free book.
Update: 03:00 AM Rather than dropping to $0.00 in the US, this is now showing a discounted price (much as happens to many non-US Kindle customers when a US publisher discounts a book). The lower price has been edited in below.
Angel By My Side: The True Story of a Dog Who Saved a Man...and a Man Who Saved a Dog ($1.99 US), by Mike Lingenfelter