If you have a few machines that are connected together, saving 1.70€ on each kinda means you could get a floating IP, or put towards a vswitch or whatever
You don't need a HTTP proxy, you could make use of existing 6to4 technologies. Cloud providers can probably offer those for free at reduced speed as part of their IPv6 package. There are also public 6to4 routers available today, ur I wouldn't trust my company's data to flow through those.
