I am using Cloudflare R2, which doesn't have egress fee and I am getting about 5k Class B operations right now. Unless Cloudflare changes their end of the deal, I think it is OK.
great to hear! please consider introducing a mechanism to suspend the download vs restarting, this may be especially valuable for those with a slower connection. With the traffic growth you'll be seeing chances are Cloudflare's enterprise team will soon be in-touch ;)