Running the numbers for 300 streamers at ~3Mbps each for ~30 hours a week works out to 12,150,000MB. That value * 4 for about monthly bandwidth usage. For a s-4vcpu-8gb instance on DO, that's ~$436 monthly overage on a $40 monthly cost droplet. Not too insane, but you're really stressing out that single droplet. You'd probably want to balance that across a few different instances across the country instead of it all being on a single droplet, in which case you're essentially rolling your own probably crappier CDN and trading CDN costs for your time managing it all.