As cheap as S3 is, I'd suspect that it'd be cost-effective to just render the core HTML (i.e., that stuff minus the date, time, user-specific bits) of a page once, throw it there and forget about it. I can't get a good read on it from http://dumps.wikimedia.org/enwiki/20150112/ ('cause I'm too lazy), but it looks like it probably would be pretty cheap, given what those files probably expand to.