We suspected a price rise was imminent for Prime subscribers in the US, especially after recent changes in the UK, and now we have the details. When you sign up or renew, youll be charged an annual rate of $99, versus the steady $79 charge that has been in place since the service first launched. An email to Prime members vaguely attributes the increase to rising fuel and transportation costs, as well as to the general expansion of streaming content and e-book lending.