Not sure what kind of money you got, but for me S3-storage costs about 0.6USD/30GB*month. Multiply this by 100 and you got a bill of 60USD/month - which is not much if you are a cash-bloated startup but not really sustainable for a bootstrapped, non-exponential (that's the point when you're talking about challenges like climate change. stop growing) business, which want's to survive on user donations, once you reach several thousand users. If you got the really cheap stuff from online.net, I recommend you don't raise any hopes in Google-scale availability...
In france you have OVH - the invest heavily in solar energy and build datacenters with low energy consumption in mind. That might be a better choice (not working for them).
OP should talk to Octave Klaba who is very approachable and a big supporter of the FOSS spirit. maybe he can cut you a good price. I'd certainly try him (add him on LinkedIn and pitch it ... or oles at ovh.net )
I did not expect to reach Google's scale during the next month so currently we are bootstrapped and rely on some AWS credits :)