There are actually a few options in egress land for us if cost is your primary concern.
If you're doing serving over http(s), you should probably be using Cloud CDN with your bucket [1] or put one of our partners like Cloudflare or Fastly with CDN Interconnect [2]. Both of these get you closer to $.04-$.08/GB depending on src/dest.
If not, and you don't care that we have a global backbone, you can get a more AWS-like network with our Standard Tier [3] (curiously with pricing squirreled away at [4], I'll file a bug). The packets will hop off our network in a hot potato / asap fashion, so you're not riding our backbone as much.
[1] http://cloud.google.com/cdn
[2] https://cloud.google.com/interconnect/docs/how-to/cdn-interc...
[3] https://cloud.google.com/network-tiers/
[4] https://cloud.google.com/network-tiers/pricing#standard_tier...
It's still way too expensive. And Cloud CDN isn't an appropriate tool for my use case. I really do just need a bunch of egress from a single location that isn't insanely expensive. $0.085/GB is in that insanely-expensive tier, for me.
I'd be happy to talk further via email; it's not secret, just not public.
Your bandwidth pricing is a joke. Yes, you got a nice network and yes you pay premiums to get transit of providers that are "hard to work with". And yes, you have dark fiber between your locations, which is costing a lot of money, but even considering those facts you are still charging at least 10x as much as your bandwidth should cost your customers.
How have you even calculated those prices? "Let's look at AWS and make it even more expensive"?
Not by enough, but they are.
But, you can build a poor-man's CDN -- varnish caches on DO/Linode/whatever where you get multiple terabytes of bandwidth for a small VM. So, you use the best object storage provider, but move most of the bits cheaply using Varnish + Route53 geo-dns.