I could have sworn AWS prices cross-zone used to be higher maybe this changed recently. Or... I was just wrong. :-)

Don't feel bad, I'd forgotten this one: "Using a public or Elastic IPv4 address => $0.01 per GB". I'm sad we still don't have a proper split horizon DNS to encourage internal IP usage, but I can't imagine charging for it in the same zone.

TL;DR: Starting at - $3.69/GB/mo (US), US$4.11/GB/mo (Ireland),

assuming reserved instances with 1yr All Upfront pricing, not counting the really huge xlarge+SSD instances.