$500/month is quite a lot. Are you hosting videos? Or some high traffic image site?

f2p game with like 2k new users per day.

Wow, congrats!

Out of curiosity, is it profitable in the end? 2k new users per day seems like a lot.

Content from https://arc.io/pricing :

    CDN Bandwidth        $0.02 per GB
    Egress (worldwide)   (76% cheaper than AWS1)
    
    Usage is billed monthly, on the first day of each calendar month.
    
    Additionally, only peer-to-peer egress bandwidth is billed; all peer-to-peer ingress bandwidth is free. For example, if a 100kB image is loaded from Arc's peer-to-peer network, only 100kB of bandwidth is billed, not 200kB (100kB of egress + 100kB of ingress).

So this is unreliable, potentially slow, and more expensive than bunnyCDN?

That makes no sense and this whole idea sounds like a pitch I would see for an ICO.

backblaze b2 is not a CDN.

Not directly, no, but stick Cloudflare in front and now you have a cdn that the storage is cheap and depending on tier you pick, cdn is free. Even the bandwidth from b2 to Cloudflare is free.

No, but it's still likely to outperform a system delivering assets over WebRTC from whatever p2p users are serving it up.

But if they don't manage to outperform it (distributed tends to be slow), it won't really matter if it's officially a CDN or not. Amazon S3 is also not a CDN, yet many use it that way.

As long as it delivers better performance, it might be worth it.

There's also BunnyCDN, which is $0.01/GB - https://bunnycdn.com/

That is better than what we are doing with cdn77 25 tb tier. I am going to look into switching.