This is the kind of thing I think NearlyFreeSpeech.net[1] would be well suited for.

They appear to have tuned their servers and business model for static web sites - if they don't serve any of your files, you pay nothing. Otherwise, you pay only for what you use.

Disclaimer: I've never used their services, but I've checked them out from time to time.

[1] https://www.nearlyfreespeech.net/services/hosting