They say they spend $12,700/month on Fastly. I guess I don't know offhand the difference between Fastly and Imgix (which they also say is their CDN), but the levels of bandwidth they're talking about are not going to be free at Cloudflare.

We serve significantly more bandwidth and requests than their 2016 numbers at under $15k compared to their $17.5k, and we're not particularly lean on infra costs being a .Net shop with Win servers and MS SQL on Azure, and I can still bring our monthly a lot closer to $10k if I can find time for some projects.

But the reality is that even thousands of dollars per month saved can take a good while to ROI against the costs of development, or more so the opportunity costs.