Cheap CDN with long origin timeout (180-200 seconds)
For a product that I'm working on, customers expect to make a single HTTP request and wait for as long as it would take for the result to be produced (typically ~160-180 seconds).
Since this product is hosted on one of the "big three" clouds, I'm hoping to reduce outbound data costs by caching repeated requests on a CDN. Of course, this CDN would need to support a timeout of 180 seconds or more.
My search only turned up CloudFront, which is hell of a expensive service ($0.0085/GB at the cheapest tier), and Cloudflare, which requires that I spend a four figure sum with them for this feature.
If this were a VPS I'd look into nginx caching, but I'm trying to save money and thus, caching it on the server instances of the "big three" would end up costing me the same data transfer pricing for every request.
Are there any alternatives to what I'm looking for?