Soul Identity, by Dennis Batchelder, has been featured at various bargain prices over the last year-and-a-half and was recently free in the Amazon UK store. Today, it's free for those in the US Kindle store (beating the penny that I paid for my copy last year).
Book Description
You can't take it with you...but what if you could? Most people believe their souls outlive their bodies. Most people would find an organization that tracks their souls into the future and passes on their banked money and memories compelling. Scott Waverly isn't like most people. He spends his days finding and fixing computer security holes. And Scott is skeptical of his new client's claim that they have been calculating and tracking soul identities for almost twenty-six hundred years. Are they running a freaky cult? Or a sophisticated con job? Scott needs to save Soul Identity from an insider attack. Along the way, he discovers the importance of the bridges connecting people's lives.